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    18 June 2022, Volume 26 Issue 17 Previous Issue   
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    Belamcandin inhibits osteoclast differentiation: its role and mechanism
    Huang Fayi, Liu Yuhao, Zhou Chi, Huang Haoran, Chen Weijian, He Wei, Wang Haibin
    2022, 26 (17):  2636-2641.  doi: 10.12307/2022.527
    Abstract ( 496 )   PDF (1088KB) ( 33 )   Save
    BACKGROUND: Receptor activator of nuclear factor kappa B ligand can mediate the activation of calcium/nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) pathway, which is crucial for osteoclast differentiation. Belamcandin can exert estrogen-like effects by activating estrogen receptors; however, less is reported on its effects on the differentiation and function of osteoclasts.
    OBJECTIVE: To explore the effect of Belamcandin on osteoclasts and its mechanism.
    METHODS: Mature mouse bone marrow macrophages cultured in vitro were differentiated and seeded into 96-well plates (6×103 cells per well), followed by inhibitory interventions with 5, 10, 20, 30, 40 μmol/L Belamcandin. Osteocyte differentiation was then observed to screen out the optimal concentration of Belamcandin with the strongest effect. Different concentrations of Belamcandin were used to deal with the differentiation of osteoclasts induced by nuclear factor κB receptor activator ligands. Tartrate-resistant acid phosphatase staining was used to observe the effects of Belamcandin on the formation and function of osteoclasts. Expression of upstream and downstream genes and proteins in the Calcium/NFATc1 signaling pathway was observed through calcium ion oscillation experiments, western blot assay and RT-qPCR detection. An approval was obtained from the Animal Experiment Ethics Committee of the First Clinical Medical College of Guangzhou University of Chinese Medicine.
    RESULTS AND CONCLUSION: Belamcandin inhibited the formation of osteoclasts in a dose-dependent manner, and 40 μmol/L Belamcandin had the strongest potential to inhibit osteoclast differentiation. Belamcandin could inhibit the mRNA expression of Acp5 (tartrate resistant acid phosphatase) gene related to the inhibition of osteoclast formation and the protein expression of c-Fos and Integrin β3, while inhibiting the expression of Ctsk, matrix metalloproteinase 9 gene, and transcription protein related to the inhibition of bone resorption function. Belamcandin could inhibit the opening frequency and intensity of calcium ion signal channels, and restrain the expression of Calcitonin receptor, Nfatc1 gene and transcription protein. To conclude, Belamcandin can inhibit the expression of Nfatc1 gene and transcription protein through the calcium ion signaling pathway induced by nuclear factor κB receptor activator ligand, thereby inhibiting osteoclast formation and bone resorption.
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    Internal heat-type acupuncture inhibits osteoblast viability and promotes bone formation in a rat model of steroid-induced avascular necrosis of the femoral head
    Tian Xinbao, Xu Jianfeng, Huang Yuan, Lai Zheying, Li Xiaolong, Liu Xiaoli, Lin Ruizhu, Zhu Ning
    2022, 26 (17):  2642-2648.  doi: 10.12307/2022.528
    Abstract ( 315 )   PDF (1307KB) ( 64 )   Save
    BACKGROUND: For the therapeutic purpose, glucocorticoids have been widely used in clinic, resulting in an increased risk of steroid-induced avascular necrosis of the femoral head (SANFH). However, the detailed pathogenesis of SANFH is not yet clear. Internal heat-type acupuncture therapy has a good clinical effect in the treatment of SANFH, but its specific mechanism has not been clearly analyzed.
    OBJECTIVE: To explore the effect of internal heat-type acupuncture on the expression of osteoprotegerin and nuclear factor kappa B receptor activator ligand (RANKL) in SANFH femoral head tissue.
    METHODS: Thirty healthy Sprague-Dawley rats without specific pathogens were randomly divided into blank group (n=10) and model group (n=20). The SANFH model was made by methylprednisolone combined with Escherichia coli endotoxin. After successful modeling, the model rats were further randomly divided into model group (n=10) and treatment group (n=10). In the treatment group, the bilateral buttocks of Sprague-Dawley rats were treated with internal heat-type acupuncture once a week for 20 minutes, and the temperature was set at 42 °C. Both the blank group and the model group were not given any treatment. The general state and behaviors (number of voluntary activities and holding power) of Sprague-Dawley rats were detected before and after intervention, and the bilateral femoral heads of rats were taken after 4 weeks of intervention. The histomorphological changes of the rat femoral head were observed by hematoxylin-eosin staining and the rate of empty lacunae was calculated. The mRNA and protein expressions of osteoprotegerin and RANKL in the femoral head tissues of each group were detected by real-time fluorescence quantitative PCR, immunohistochemical staining and western blot, respectively.
    RESULTS AND CONCLUSION: The behavioral scores of rats in the model and treatment groups were significantly lower than those in the blank group (P < 0.01). After intervention, the behavioral scores of rats in the treatment group were significantly higher than those in the model group. Compared with the blank group, the histomorphology of the femur became significantly worse and the rate of empty bone lacuna was significantly higher in the model group (P < 0.001). Compared with the model group, the histomorphology of the femur was significantly improved and the rate of empty bone lacuna was decreased in the treatment group (P < 0.05). Compared with the blank group, the expression levels of RANKL protein and mRNA in the rat femoral head tissue were significantly higher in the model group, while the protein and mRNA expression levels of osteoprotegerin were significantly lower in the model group (P < 0.001). After intervention, the expression levels of RANKL protein and mRNA in the rat femoral head tissue in the treatment group were significantly lower than those in the model group, while the protein and mRNA expression levels of osteoprotegerin were significantly higher than those in the model group (P < 0.05). To conclude, internal heat-type acupuncture may up-regulate the expression of osteoprotegerin, down-regulate the expression of RANKL, and inhibit the function and activity of osteoclasts, thus inhibiting bone resorption and promoting new bone formation and bone tissue repair.
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    Echinops latifolius, a Mongolian medicine, for treating cartilage injury in a rabbit model of knee osteoarthritis
    Kong Lingyue, Hu Yongcheng, Han Changxu
    2022, 26 (17):  2649-2653.  doi: 10.12307/2022.529
    Abstract ( 663 )   PDF (744KB) ( 29 )   Save
    BACKGROUND: Osteoarthritis is clinically common, which is the most common cause of chronic disability in middle-aged and elderly people. Echinops latifolius, as a Mongolian medicine, has positive therapeutic effect in bone diseases. However, its effect and mechanism on osteoarthritis remain to be investigated.
    OBJECTIVE: To investigate the effect of Echinops latifoliuss on knee osteoarthritis and on the expression of type II collagen and matrix metalloproteinase 13.
    METHODS: Thirty healthy Chinese white rabbits were selected and randomly divided into a control group (n=10) and a knee osteoarthritis group (n=20). Rabbits in the knee osteoarthritis group were fixed with cast plaster for 8 weeks to prepare knee osteoarthritis models. After successful modeling, rabbits in the knee osteoarthritis group were subdivided into an Echinops latifolius group and a model control group. In the Echinops latifolius group, 3.25 g/L Echinops latifolius was administered at a dose of 20 mL/kg by gavage. The control and model control groups were intragastrically administered normal saline at a dose of 20 mL/kg. Rabbits in each group were given continuous gastric gavage for 90 days, and then killed under anesthesia. Knee joint cartilage was taken and sliced. Hematoxylin-eosin staining was use to observe the histological changes of cartilage. RT-PCR was used to detect the mRNA expression of type II collagen and matrix metalloproteinase 13, and immunohistochemical staining was used to detect the protein expression of type II collagen and matrix metalloproteinase 13. 
    RESULTS AND CONCLUSION: Echinops latifolius could improve osteoarthritis-induced cartilage damage of and promote the proliferation of chondrocytes and matrix. In addition, Echinops latifolius could promote the mRNA and protein expression of type II collagen in osteoarthritis, and inhibit the high expression of matrix metalloproteinase 13 at mRNA and protein levels caused by osteoarthritis. To conclude, Echinops latifolius can promote the expression of type II collagen and inhibit the expression of matrix metalloproteinase 13, thereby playing a positive role in the prevention and treatment of osteoarthritis.
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    Effects of zoledronic acid on alveolar bone metabolism and nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome in the alveolar bone of ovariectomized osteoporosis rats
    Huo Hua, Liu Guanjuan, Song Na, Zhou Qian, Cheng Yuting, Luo Shanshan, Liao Jian
    2022, 26 (17):  2660-2666.  doi: 10.12307/2022.531
    Abstract ( 506 )   PDF (1183KB) ( 39 )   Save
    BACKGROUND: Zoledronic acid is a classical bisphosphate bone resorption inhibitor; however, its effect and mechanism on the mandibular alveolar bone metabolism are not clarified.
    OBJECTIVE: To study the effects of zoledronic acid on the expression of bone resorption and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in the mandibular alveolar bone of ovariectomized osteoporosis rats.
    METHODS: Thirty-six female Sprague-Dawley rats were randomly divided into three groups (n=12 per group): sham group, osteoporosis group (bilateral ovariectomy), and zoledronic acid group (bilateral ovariectomy, followed by administration of zoledronic acid). Twelve weeks after ovariectomy, the rats in the zoledronic acid group were given subcutaneous injection of 20 μg/kg zoledronic acid, and the corresponding doses of saline were injected subcutaneously in the sham and osteoporosis groups. The rat’s mandibular alveolar bone was separated and removed at 4 weeks after administration. Alveolar bone mass band alveolar bone absorption were observed by Micro-CT, the pathological changes of the alveolar bone were observed using hematoxylin-eosin staining, the number of osteoclasts in alveolar bone was observed by tartrate resistant acid phosphatase staining, the expression of NLRP3 was determined by immunohistochemical technique, and the protein levels of NLRP3, Caspase-1, and interleukin-1β in the alveolar bone were detected using western blot.
    RESULTS AND CONCLUSION: Compared with the sham group, the bone trabecular structure was broken in the osteoporosis group, with the emergence of a large number of bone resorption lacunae and uneven surface of the alveolar bone; meanwhile, percent bone volume, trabecular thickness, bone mineral density in alveolar bone were lower, trabecular separation were increased, and the number of osteoclast was significantly increased in the osteoporosis group (P < 0.05). Compared with the osteoporosis group, alveolar bone microstructure in the zoledronic acid group was improved, and the above pathological symptoms were alleviated obviously. Immunohistochemistry staining results showed that the expression level of NLRP3 protein was significantly higher in the osteoporosis group than the sham group (P < 0.05), and the expression of NLRP3 was significantly lower in the zoledronic acid group than the osteoporosis group (P < 0.05). Western blot results indicated that the expression levels of NLRP3, Caspase-1 and interleukin-1β proteins was higher in the osteoporosis group than the sham group, while the protein levels in the zoledronic acid were lower than those in the osteoporosis group (P < 0.05). To conclude, zoledronic acid can effectively inhibit the expression of NLRP3, Caspase-1 and inteleukin-1β in the alveolar bone of osteoporotic rats, and inhibit mandibular alveolar bone resorption by reducing the number of osteoclasts.
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    Effect of Gushukang on osteogenic differentiation in a Beagle dog model during orthodontic root resorption and its mechanism
    Wan Zhe, Du Jun, He Jing, Hu Yang
    2022, 26 (17):  2654-2659.  doi: 10.12307/2022.530
    Abstract ( 399 )   PDF (1211KB) ( 90 )   Save
    BACKGROUND: Root resorption is a common complication in molar intrusion, which is unpredictable. There is currently no effective treatment in clinical practice. Gushukang can promote the proliferation and differentiation of osteoblasts and inhibit the activity of osteoclasts. It is mainly used for the prevention and treatment of osteoporosis and bone defects, but there are few studies on root resorption.
    OBJECTIVE: To investigate the effect of Gushukang on osteogenic differentiation in a Beagle dog model of orthodontic root resorption and its possible mechanism.
    METHODS: Sixteen male Beagle dogs were randomly divided into a normal control group (n=4), a distilled water group (n=6) and a Gushukang group (n=6). The normal control group did not undergo any intervention. A bilateral maxillary first molar intrusion animal model (orthodontic surgery) was established in the distilled water group and Gushukang group. After the model was made, distilled water and Gushukang [2.1 g/(kg·d)] were given by gavage in the distilled water and Gushukang groups, respectively. At the 6th, 9th, and 12th weeks after modeling, the first molar tissue was taken. Quantitative real-time polymerase chain reaction was used to detect the mRNA expression of runt-related transcription factor 2, dentin sialophosphoprotein, bone morphogenetic protein 2, and osteocalcin. Western blot was used to detect the protein expression of runt-related transcription factor 2 and beta-catenin.
    RESULTS AND CONCLUSION: General observation showed that the first molar appeared to be significantly intruded with time, and the effect was most obvious at the 12th week. Quantitative real-time polymerase chain reaction test showed that, at the same time point, the mRNA expression of bone morphogenetic protein 2, dentin sialophosphoprotein, runt-related transcription factor 2 and osteocalcin in the Gushukang group was higher than that in the other two groups (P < 0.05). The mRNA expression of bone morphogenetic protein 2 and runt-related transcription factor 2 in the distilled water group was lower than that in the normal control group (P < 0.05). And there was no significant difference in the mRNA expression of bone morphogenetic protein 2, dentin sialophosphoprotein, runt-related transcription factor 2 and osteocalcin at three observational time points in the Gushukang group (P > 0.05). Western blot analysis showed that, at the same time point, the protein expression of beta-catenin and runt-related transcription factor 2 in the Gushukang group was higher than that in the other two groups (P < 0.05), and the protein expression of beta-catenin and runt-related transcription factor 2 in the distilled water group was lower than that in the normal control group (P < 0.05). The protein expression of runt-related transcription factor 2 in the Gushukang group at 9 and 12 weeks after modeling was higher than that at 6 weeks after modeling (P < 0.05), and the protein expression of beta-catenin at 12 weeks after modeling was higher than that at 9 weeks after modeling (P < 0.05). To conclude, Gushukang may promote osteogenic differentiation in orthodontic molar tissue and maintain the bone matrix in Beagle dogs by activating bone morphogenetic protein 2 and runt-related transcription factor 2/beta-catenin pathway.
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    Characteristics of dental inclination in different vertical skeletal types of skeletal class II malocclusion: a three-dimensional imaging evaluation
    Zhou Xingyu, Jia Ying, Li Zhongwei, Ding Qi
    2022, 26 (17):  2625-2630.  doi: 10.12307/2022.525
    Abstract ( 570 )   PDF (909KB) ( 80 )   Save
    BACKGROUND: Based on cone-beam CT measurement, the research group has found that the dental inclination characteristics of class III malocclusion are compensated due to the influence of the vertical direction. As a population group with a high incidence of class II malocclusion, there are different diagnoses and treatment strategies in Chinese people with different skeletal types, which is speculated to be related to the compensation difference of dental inclination.
    OBJECTIVE: To explore the sagittal and coronal inclination characteristics of the whole tooth axis in different vertical skeletal types of class II malocclusion in order to provide guidance for clinical diagnosis and treatment. 
    METHODS: Dicom data of cone-beam CT images were collected from 70 patients with skeletal class II malocclusion (middle angle: 30 cases, high angle: 20 cases, low angle: 20 cases) and 30 patients with middle-angle skeletal class I. The tipping angle and torque of all teeth were measured and compared by the software Invivo 5.1. 
    RESULTS AND CONCLUSION: (1) In skeletal class II malocclusion, there was a statistically significant difference in the dental inclination of low-angle skeletal class II and high-/middle-angle skeletal class II, while the dental inclination of high- and middle-angle skeletal class II was basically similar. (2) Comparison of low-angle with middle- and high-angle skeletal class II: In the sagittal plane, the positive torque of the anterior upper teeth decreased and the anterior lower teeth were relatively upright, while mesio-inclination of the upper posterior teeth decreased and mesio-inclination of the lower posterior teeth increased. In the coronal plane, there was a significant difference in the trend of mesio-inclination of the upper and lower canines with low-angle class II (P < 0.05). (3) Comparison of skeletal class II and middle-angle skeletal class I: In the sagittal plane, except for anterior lower teeth, the characteristics of tooth inclination of middle-/high-angle class II and middle-angle class I are basically similar; however, there was significant difference between the two groups and low-angle class II (P < 0.05). For the anterior lower teeth, the skeletal class II malocclusion group showed no significant difference; however, compared with middle-angle class I, the labial inclination of the anterior lower teeth had increased. In the coronal plane, for the posterior teeth, the inclination characteristics of skeletal class II were similar. However, compared with skeletal class I, the posterior upper teeth showed a lingual inclination trend and the posterior lower teeth showed a buccal inclination trend. Moreover, there were statistically significant differences among upper second premolars, first molars, second molars, and lower first molars (P < 0.05). For the anterior teeth, there was no significant difference between class II and class I malocclusions. To conclude, skeletal class II malocclusion has the dental compensation of the anterior lower and posterior teeth, and the dental compensation of low-angle class II is more significant than that of high- and middle-angle class II. The sagittal inclination of low-angle skeletal class II malocclusion is related to the rotation of the jaw.
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    Constructing a mouse model of periodontitis with occlusal trauma
    Yang Qin, Wang Min
    2022, 26 (17):  2667-2672.  doi: 10.12307/2022.532
    Abstract ( 461 )   PDF (840KB) ( 93 )   Save
    BACKGROUND: Although it is essential to establish a model of periodontitis with occlusal trauma for exploring the role of occlusal trauma in periodontitis, there is yet no stable and reliable method to establish an animal model of periodontitis with occlusal trauma.
    OBJECTIVE: To establish a stable, reliable and efficient animal model of periodontitis with occlusal trauma.
    METHODS: Animal models of occlusal trauma, periodontitis, and periodontitis with occlusal trauma were made in BALB/c mice by composite resin bonding, oral implantation of Porphyromonas gingivalis, and their combination. Healthy mice acted as control group. Micro-CT scan was used to detect alveolar bone resorption and fluorescent quantitative PCR was used to detect the expression of tumor necrosis factor α, interleukin 1β, and interleukin 6 in the alveolar bone, in order to determine whether the animal model of periodontitis with occlusal trauma was successfully established.  
    RESULTS AND CONCLUSION: Compared with the control group, there was no obvious alveolar bone resorption in the simple occlusal trauma group, while the alveolar bone resorption was aggravated in the simple periodontitis group and the periodontitis with occlusal trauma group, especially in the latter group. Compared with the control group, the relative mRNA expression of tumor necrosis factor α and interleukin 1β was significantly increased in the simple occlusal trauma group (P < 0.01). Compared with control group, the expression levels of tumor necrosis factor α, interleukin 1β, and interleukin 6 mRNA were significantly up-regulated in the simple periodontitis group and the periodontitis with occlusal trauma group, and moreover, these expression levels were higher in the periodontitis with occlusal trauma group than the simple periodontitis group (P < 0.01). All these suggest that the animal model of periodontitis with occlusal trauma is successfully established.
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    Effect of connective tissue growth factor on the secretion of type I and III collagen in tenocytes
    Wang Quanzhen, Xiao Yingfeng, Wan Shengxiang, Zhang Jian, Zhou Bo, Meng Fanbin, Yu Longbiao, Yu Fei
    2022, 26 (17):  2673-2677.  doi: 10.12307/2022.533
    Abstract ( 521 )   PDF (759KB) ( 34 )   Save
    BACKGROUND: Tendon rupture is a common thorny problem in orthopedics, and collagen secretion in tenocytes affects the repair process of tendon rupture. Connective tissue growth factor affects the fibrosis process of tissues and organs, and plays an important role in the secretion of cell collagen. However, its effects on the secretion of tenocyte collagen have been rarely reported.
    OBJECTIVE: To investigate the expression of type I collagen and type III collagen in primary chicken tenocytes stimulated in vitro with different concentrations of connective tissue growth factors. 
    METHODS: Six Leghorn chickens, aged 8 weeks, were killed, and deep digital flexor tendon was obtained to culture primary tenocytes. Immunofluorescence staining for type I and III collagen was used to detect the primary tenocytes. Then passage 4 tenocytes were stimulated with connective tissue growth factors at different concentrations (0, 5, 10, 20, 50, 100, 200, and 500 μg/L) for 4 days. Real-time fluorescence quantitative PCR and enzyme-linked immunosorbent assay were used to detect the mRNA and protein expression of type I collagen and type III collagen in different groups of primary tenocytes. 
    RESULTS AND CONCLUSION: The primary cultured cells were identified as tenocytes by type I and III collagen immunofluorescence staining. Real-time fluorescence quantitative PCR detection showed that the mRNA expression of type I collagen and type III collagen was increased in tenocytes after connective tissue growth factor stimulation. Enzyme-linked immunosorbent assay detection showed that the protein expression of type I collagen and type III collagen was increased in tenocytes after connective tissue growth factor stimulation (P < 0.01), and both increased gradually with the increase of connective tissue growth factors concentration. Connective tissue growth factors at 20 and 50 μg/L might be the best concentrations to stimulate primary tenocytes to produce type I collagen and type III collagen in vitro. Therefore,  connective tissue growth factors within a certain concentration range can promote the secretion of type I collagen and type III collagen in primary chicken tenocytes.
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    Single-bundle anatomical reconstruction of the anterior cruciate ligament with residual ligament stump is beneficial to the recovery of proprioception
    Liao Xinyu, He Lu, Li Yanlin, Wang Fuke, Zhou Xiaoxiang, Wang Xu, Zhong Ruiying, Wang Guoliang
    2022, 26 (17):  2631-2635.  doi: 10.12307/2022.526
    Abstract ( 392 )   PDF (850KB) ( 38 )   Save
    BACKGROUND: After an anterior cruciate ligament rupture, the proprioception of the knee joint will be damaged,  which thereby impacts the stability of the knee joint. Reconstruction of the anterior cruciate ligament through surgery is the current main treatment method; however, the recovery of proprioception of patients undergoing different reconstruction surgeries is different after different reconstruction methods.
    OBJECTIVE: To investigate the recovery of proprioceptive function of the knee joint after the single-bundle anatomical reconstruction of the anterior cruciate ligament with residual stump under arthroscope.
    METHODS: Seventy patients with anterior cruciate ligament rupture who were admitted at the Department of Sports Medicine, the First Affiliated Hospital of Kunming Medical University  from January 2015 to December 2018 and met the selection criteria were enrolled and randomly divided into two groups. In the experimental group, the anterior cruciate ligament was reconstructed through a single-bundle anatomy with residual stump, while in the control group the anterior cruciate ligament was reconstructed through a single-bundle anatomy without residual stump. After operation, the Lysholm score, International Knee Documentation Committee score, and threshold to detection of passive motion were used to evaluate the knee joint function and proprioception recovery of the patients. All enrolled patients signed the relevant informed consent forms, and the trial protocol was approved by the Ethics Committee of the First Affiliated Hospital of Kunming Medical University.
    RESULTS AND CONCLUSION: At 3 and 6 months after operation, the Lysholm score and International Knee Documentation Committee score in the experimental group were significantly higher than those in the control group, and the threshold to detection of passive motion was significantly lower than that in the control group (P < 0.05). There was no significant difference in these scores between the two groups at 12 months after operation (P > 0.05). To conclude,  single-bundle anatomical reconstruction of the anterior cruciate ligament with residual stump is beneficial to the early recovery of proprioception and stability of the knee joint. 
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    Establishment of a severe heatstroke pig model under high-temperature and high-humidity environment
    Yang Yanwen, Zhang Jing, Mao Yuling, Ni Jun, Mao Libin, Yao Lu, Wang Huiying, Liu Qiuming, Ma Zhenzhen
    2022, 26 (17):  2678-2684.  doi: 10.12307/2022.534
    Abstract ( 450 )   PDF (1501KB) ( 38 )   Save
    BACKGROUND: Due to the small size of severe heatstroke small animal models, there is a limitation to the implementation of blood purification and other clinical interventions, while mostly used large animal models, such as baboon, are expensive. The Bama miniature pig used in this study has good genetic stability, and is similar to the human body in terms of body temperature regulation and cardiovascular response, which is also easy to obtain and has low cost.
    OBJECTIVE: To prepare the pig model of severe heatstroke under high temperature and high humidity environment, thereby providing an experimental platform for blood purification and other intervention treatments.
    METHODS: Twelve male experimental miniature pigs were randomly divided into two groups (n=6 per group): group A (control) and group B in which a pig model of severe heatstroke was established. The experimental conditions are as follows: group A: temperature 35-37 °C; group B: temperature 44-47 °C; the humidity was (65±5)% in both groups; and the experiment in each group lasted for 4 hours. The autonomic state, conjunctiva and levator ani reflex were recorded in detail. The vital signs of experimental animals were continuously monitored by multi-channel physiological recorder. The whole blood cell count, liver and kidney function, creatine kinase, blood coagulation function and urine routine were detected before and after modeling. After the end of the experiment, the important organs and tissues of the experimental animals were taken for pathological examination. The study protocol was approved by the Medical Ethics Committee of the 83rd Army Hospital of Chinese PLA.
    RESULTS AND CONCLUSION: Pigs in the two groups were exposed to different environmental conditions for 4 hours. There were significant changes in autonomous behaviors and vital signs of pigs in group B before and after the experiment, and also in laboratory examination results, including whole blood white blood cells, activated partial thromboplastin time, prothrombin time, blood potassium, creatinine and urea nitrogen, aminotransferase and creatine kinase levels (P < 0.05 or P < 0.01). Pathomorphological observations showed multiple organ injuries. There was no significant abnormality in autonomous behaviors of pigs in group A, and there were slight changes in vital signs and laboratory examination results. To conclude, after being exposed to the constant environment of 44-47 °C and humidity of (65±5)% for 4 hours, the pigs present with significant abnormalities in autonomous behaviors, vital signs and laboratory tests, which can reach the standard of severe heatstroke. The pig model of severe heatstroke has good repeatability, which can meet the needs of blood purification for clinical severe heatstroke.
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    Effects of aerobic exercises on JAK2/STAT5 signal pathway in the liver of mice with non-alcoholic fatty liver disease
    Zhang Shuling, Li Junhan, Wang Jiaqian, Li Yalong, Wang Chun
    2022, 26 (17):  2690-2695.  doi: 10.12307/2022.536
    Abstract ( 413 )   PDF (955KB) ( 36 )   Save
    BACKGROUND: The Janus kinase 2/signal transducer and activator of transcription 5 (JAK2/STAT5) signaling pathway plays an important role in lipid metabolism. The effective prevention and treatment of non-alcoholic fatty liver by exercise is closely related to the improvement of visceral lipid deposition and lipid metabolism.
    OBJECTIVE: To explore the effect of aerobic exercise on the JAK2/STAT5 signaling pathway in the liver of non-alcoholic fatty liver mice and its possible mechanism.
    METHODS: Forty-eight C57BL/6 male mice aged 6 weeks were randomly divided into a normal diet group (n=24) and a high-fat diet induction group (n=24). On the 10th weekend, four mice were randomly selected from each group for oil red O staining to observe the pathological morphological changes of the liver. After successful modeling, the normal diet group was randomly divided into a normal diet+quiet group (n=10) and a normal diet+exercise group (n=10); the high-fat diet induction group was randomly divided into a non-alcoholic fatty liver+quiet group (n=10) and a non-alcoholic fatty liver+exercise group (n=10), followed by 8 weeks of intervention until the end of the experiment. Liver pathological changes were observed, and prolactin receptor, JAK2, and phosphorylation of JAK2 and STAT5 in the liver of mice were detected. 
    RESULTS AND CONCLUSION: Compared with the normal diet+quiet group, hepatic steatosis was increased and the protein expression of JAK2/STAT5 signaling pathway in the liver was decreased in the non-alcoholic fatty liver+quiet group. Compared with the non-alcoholic fatty liver+quiet group, hepatic steatosis was decreased and the protein expression of JAK2/STAT5 signaling pathway in the liver was increased in the non-alcoholic fatty liver+exercise group. The liver pathological indicators were significantly negatively correlated with prolactin receptor, JAK2, and phosphorylation of JAK2/STAT5 (P < 0.05). To conclude, aerobic exercise intervention can improve liver lipid deposition and the degree of hepatic steatosis by regulating the JAK2/STAT5 signaling pathway in the liver of mice with non-alcoholic fatty liver.
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    Rapid establishment of rat liver transplantation model by portal vein preferential reverse anastomosis
    Zhang Jixiang, Yan Hongxian, Xuan Juanjuan, Bai Hongtai, Wang Yaoquan, Wei Sidong, Chen Guoyong
    2022, 26 (17):  2696-2701.  doi: 10.12307/2022.537
    Abstract ( 355 )   PDF (2245KB) ( 57 )   Save
    BACKGROUND: The traditional “two cuff” model of rat liver transplantation takes a long time to establish, which is difficult to grasp and adapt to the training of graduate students.
    OBJECTIVE: As per the characteristics of multi-step establishment of liver transplantation model in rats, to rationally combine the time and method of each step so as to shorten the learning time and reduce the difficulty of operation, thereby rapidly establishing a rat model of liver transplantation.
    METHODS: The portal vein was preferentially anastomosed using the two-cuff method when the blood flow of the inferior vena cava was unobstructed. The cuff was anastomosed reversely by placing the donor liver in the lower abdomen of rats (portal vein preferential anastomosis group). The rat liver transplantation model was established and compared with the traditional rat liver transplantation model (traditional transplantation group). The learning time curve, portal vein occlusion time, anhepatic phase time, inferior vena cava occlusion time, recipient operation time, and postoperative survival of the two groups were statistically analyzed.
    RESULTS AND CONCLUSION: The learning curves of 32 cases in the traditional transplantation group and 30 cases in the portal vein preferential anastomosis group were analyzed. The learning time of portal vein preferential anastomosis group was shorter than that of traditional transplantation group. The operation time of 12 rats in the traditional transplantation group and 20 rats in the portal vein preferential anastomosis group which survived over 2 days was statistically analyzed. Parameter test analysis showed that the portal vein occlusion time in the portal vein preferential anastomosis group was slightly longer than that in the traditional transplantation group, but there was no significant difference. However, the blocking time of the suprahepatic inferior vena cava in the portal vein preferential anastomosis group was (15.0±2.2) minutes, which was significantly shorter than (21.3±2.1) minutes in the traditional transplantation group (P < 0.05), and the time of infrahepatic inferior vena cava occlusion in the portal vein preferential anastomosis group was (25.0±2.9) minutes, which was significantly shorter than that [(32.5±3.2) minutes] in the traditional transplantation group (P < 0.05). There was no significant difference in donor perfusion time, donor operation time, donor liver repair time and recipient operation time between the two groups. Rat model of liver transplantation with portal vein preferential anastomosis can shorten the learning cycle, reduce the difficulty of operation, and provide a relatively reliable method for beginners to quickly master the establishment of rat liver transplantation model, which is suitable for learning and promotion.
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    Establishment and evaluation of neurogenic bladder model in rats with type 2 diabetes mellitus
    Han Xuke, Chen Yiding, Chen Huizhen, Yang Xiaomei, Hong Peipei, Chen Qiu
    2022, 26 (17):  2713-2719.  doi: 10.12307/2022.540
    Abstract ( 416 )   PDF (961KB) ( 110 )   Save
    BACKGROUND: The incidence of neurogenic bladder in type 2 diabetes is increasing. However, its pathogenesis is not clear and there is no effective treatment method. It is of great significance to construct an efficient and stable animal model for the study on its pathogenesis and treatment methods. 
    OBJECTIVE: To establish a rat model of neurogenic bladder in type 2 diabetes mellitus. 
    METHODS: Male Sprague-Dawley rats were divided randomly into control (n=10) and model (n=45) groups. Control group was given 8-week normal diet, and model group was given 8-week high fat diet. At the 4th week of high-fat diet, the model rats were randomly divided into three groups (n=15 per group) followed by single intraperitoneal injection of 20, 25, and 50 mg/kg streptozotocin respectively. The control group was treated with the equal amount of sodium citrate buffer. The general condition was observed, and the body mass and blood glucose level were recorded at 0, 4, and 8 weeks. At the 8th week, urodynamic parameters and bladder wet weight were detected, and histological changes of the bladder were observed using hematoxylin-eosin staining. 
    RESULTS AND CONCLUSION: High-fat diet combined with single intraperitoneal injection of streptozotocin (35 mg/kg) had higher survival rate and successful modeling rate (80%). Compared with the control group, the bladder capacity and residual urine volume increased, the maximum bladder pressure decreased, the wet weight and compliance of the bladder increased after single intraperitoneal injection of 35 mg/kg streptozotocin (P ≤ 0.05). In conclusion, 8-week high-fat diet combined with single intraperitoneal injection of 35 mg/kg streptozotocin is the best method to establish a rat model of type 2 diabetes mellitus with neurogenic bladder.
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    Calcium-sensitive receptors influence pulmonary vascular remodeling in neonatal mice with persistent pulmonary hypertension
    Zhu Yaping, Li Xiang, Chen Zhiwen, Liu Ying, Zhao Wenzhuo, Ma Ketao, Gu Qiang
    2022, 26 (17):  2708-2712.  doi: 10.12307/2022.539
    Abstract ( 476 )   PDF (959KB) ( 30 )   Save
    BACKGROUND: Previous studies have shown the up-regulated expression of calcium-sensitive receptors in the neonatal mouse model of persistent pulmonary hypertension. The up-regulation trend is more obvious in the calcium-sensitive receptor agonist group, while the expression is declined somewhat in the calcium-sensitive receptor inhibitor group.
    OBJECTIVE: To explore the mechanism of calcium-sensitive receptors in pulmonary remodeling in neonatal mice with hypoxia-induced persistent pulmonary hypertension. 
    METHODS: Eighty newborn C57BL/6 mice were randomly divided into four groups. Mice in the hypoxic group, the hypoxic+agonist group (hereinafter referred to as agonist group), and the hypoxic+antagonist group (hereinafter referred to as antagonist group) were placed in a hypoxic chamber simultaneously (oxygen concentration 12%). In addition, the agonist and antagonist groups were given intraperitoneal injection of calcium-sensitive receptor agonist GdCl3 (16 mg/kg) and inhibitor NPS2390 (1 mg/kg) once a day respectively. Mice in the normoxia group were exposed to air and injected with the same amount of normal saline daily as that in the hypoxic group. After 14 days, heart and lung tissues were removed. The thickness of ventricular wall and pulmonary vascular wall was measured and alveolar morphology was observed. The level of B-type brain natriuretic peptide was determined by enzyme linked immunosorbent assay. Western blot and immunohistochemistry were used to detect the expression and localization of caveolin-1 protein in mouse lung tissue, and qRT-PCR was used to detect the expression of caveolin-1 mRNA. The study protocol was approved by the Experimental Animal Ethic Committee of the First Affiliated Hospital of Shihezi University School of Medicine (approval No. 2018-172-01).
    RESULTS AND CONCLUSION: After 14 days of hypoxia, the wall thickness of small pulmonary arterioles in mice increased, and the thickness ratio of right ventricle to left ventricle and B-type brain natriuretic peptide level increased in the hypoxic group compared with the normoxia group. The average alveolar lining interval was widened and the radial alveolar count decreased in the hypoxic group compared with the normoxia group. Western blot and qRT-PCR results showed that the expression levels of caveolin-1 protein and mRNA were up-regulated hypoxic group compared with the normoxia group (P < 0.05). These changes were more significant in the agonist group (P < 0.05), while the inhibitor group reversed the changes caused by hypoxia (P < 0.05). To conclude, calcium-sensitive receptor affects the vascular remodeling in the lung of neonatal mice with persistent pulmonary hypertension, and the mechanism may be related to the changes in the caveolin-1 expression.
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    Protective effect of exercise preconditioning on lung injury induced by hypobaric hypoxia in rats based on the nuclear factor E2-related factor 2/antioxidant response element signal pathway
    You Kun, Liu Yuanxin
    2022, 26 (17):  2702-2707.  doi: 10.12307/2022.538
    Abstract ( 439 )   PDF (999KB) ( 27 )   Save
    BACKGROUND: Hypobaric hypoxia can affect the lung function of rats, triggering cell apoptosis in lung tissue and inducing pulmonary vascular remodeling. Exercise preconditioning can relieve lung injury caused by pulmonary vascular remodeling by up-regulating the nuclear factor E2- related factor 2 (Nrf2)/antioxidant response element (ARE) pathway in lung tissue.
    OBJECTIVE: To explore the protective effect of exercise preconditioning on lung injury induced by hypobaric hypoxia in rats based on the Nrf2/ARE signal pathway. 
    METHODS: Eighty Sprague-Dawley rats were randomly divided into four groups with 20 rats in each group: normal group, model group, short-term exercise precondition group (short-term group) and long-term exercise preconditioning group (long-term group). The short-term group was required to swimming training for 1 continuous week, while the long-term group was required to exercise for 3 weeks same as the short-term group. On the next day after the last exercise preconditioning, the rats in the short- and long-term groups were slowly and uniformly decompressed to 8 000 meters above sea level (rising at a speed of 10 m/s) in a hypobaric chamber, and underwent continuous hypoxia for 48 hours, during which the rats in the normal group were given any treatment. Pathological changes of the lung tissue was observed by hematoxylin-eosin staining, pulmonary vascular remodeling was observed by elastic van gieson staining, apoptosis in pulmonary artery smooth muscle cells was detected by TUNEL staining, and vascular endothelial growth factor and α-smooth muscle actin in pulmonary artery tissue were detected by immunohistochemistry. The expression of reactive oxygen species in blood, activities of superoxide dismutase activity, glutathione peroxidase and catalase in lung tissue were detected by reactive oxygen species kit, xanthine oxidase method, dithiodinitrobenzoic acid and ammonium molybdate chemical colorimetric method, respectively. Nrf2/ARE signaling pathway protein in rat lung tissue was detected using western blot assay. Respiratory frequency, tidal volume and ventilation per minute in each rat were recorded. 
    RESULTS AND CONCLUSION: Compared with the normal group, in the model group, the respiratory frequency was significantly increased, the tidal volume and minute ventilation were significantly decreased, the medial thickness of pulmonary arterioles and the degree of vascular muscularization were significantly increased, the apoptosis rate, the expression of α-smooth muscle actin and vascular endothelial growth factor, reactive oxygen species level and the expression of Nrf2 and ARE were significantly increased, and the activities of superoxide dismutase activity, glutathione peroxidase and catalase were significantly decreased. Compared with the model group, in both short- and long-term groups, the respiratory frequency was significantly lowered, the tidal volume and ventilation per minute were significantly increased, the medial thickness and the degree of vascular muscularization in the lung tissue were significantly reduced, the apoptosis rate, α-smooth muscle actin and vascular endothelial growth factor expression, reactive oxygen species level and the expression of Nrf2 and ARE were significantly decreased, and the activities of superoxide dismutase activity, glutathione peroxidase and catalase were significantly increased (P < 0.05). These changes were more obvious in the long-term group than the short-term group. To conclude, hypobaric hypoxia can affect lung function and cause lung tissue injury, exercise preconditioning can enhance the activities of superoxide dismutase activity, glutathione peroxidase and catalase, decrease the level of reactive oxygen species and the expression of α-smooth muscle actin and vascular endothelial growth factor by up-regulating Nrf2/ARE pathway in lung tissue, so as to improve the antioxidant capacity of lung tissue, reduce the apoptosis rate of lung tissue and improve the symptoms of pulmonary vascular remodeling, thus improving lung injury induced by hypobaric hypoxia. And long-term exercise preconditioning is superior to short-term exercise preconditioning in protecting lung tissue.
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    Effects of sirtinol versus dexamethasone on the levels of recombinant sirtuin 1 and interleukin-5 in asthmatic mice
    Luo Qiurui, Song Xiaoqin, Wang Rongli
    2022, 26 (17):  2720-2725.  doi: 10.12307/2022.541
    Abstract ( 389 )   PDF (1226KB) ( 88 )   Save
    BACKGROUND: Asthma is a chronic inflammatory disease of the respiratory tract mediated by a variety of inflammatory cells. Recombinant sirtuin 1 (SIRT1) is closely related to the occurrence of asthma and airway hyperresponsiveness. 
    OBJECTIVE: To compare the effects of sirtinol (a specific inhibitor of SIRT1) in different concentrations and dexamethasone on the expression of SIRT1 gene and interleukin-5 in asthmatic mice, and to provide a new theoretical basis for the role of SIRT1 in asthma pathogenesis and related treatments. 
    METHODS: Forty-two female Balb/c mice were randomly divided into seven groups: blank control group, asthma group, dexamethasone group, sirtinol group 1, sirtinol group 2, sirtinol group 3, and sirtinol group 4. In the latter six groups, a mouse model of asthma was prepared as follows: mice were intraperitoneally given 0.2 mL of antigen suspension (100 μg of ovalbumin OVA + 2 mg of aluminium hydroxide + 0.2 mL of normal saline) for sensitization on days 1, 8 and 15, and then given 40 μL of 2% ovalbumin solution (2 g of ovalbumin +100 mL of normal saline) via the nasal cavity to stimulate high airway response for 7 continuous days. Mice in the blank control group were given the same volume of normal saline. The dexamethasone group was intraperitoneally injected with 0.2 mL of dexamethasone solution (3 mg/kg) 30 minutes before excitation, and the sirtinol groups 1, 2, 3, and 4 were injected intraperitoneally with 0.12 mL of sirtinol solution at different concentrations (0, 0.05, 0.5, and 3.0 mg/kg), respectively, at 1 hour before first excitation and 3 hours after last excitation. Additionally, the sirtinol group 1 was intraperitoneally injected with 0.12 mL of 0.125% dimethyl sulfoxide solution. The mice were sacrificed 24 hours after the last excitation, and lung tissue morphology was observed by hematoxylin-eosin staining. The expression of SIRT1 in the lung tissue of mice was detected by western blot. The mRNA levels of SIRT1 and internal reference gene (β-actin) in the lung tissue of mice was detected by real-time fluorescence quantitative PCR. Interleukin-5 content in bronchoalveolar lavage fluid was detected by enzyme-linked immunosorbent assay. 
    RESULTS AND CONCLUSION: Inflammation was relieved in the dexamethasone group compared with the asthma group, but not significantly in the sirtinol group 1. Inflammation reduction was progressively decreased in the sirtinol groups 2, 3, and 4. Compared with the asthma group, SIRT1 expression was decreased in the dexamethasone group and the sirtinol groups 1, 2, 3, 4, and was lowest in the sirtinol group 2. The expression of SIRT1 mRNA in the lung tissue was highest in the asthma group and lowest in the blank control group. The expression level of SIRT1 mRNA in the asthma group was significantly higher than that of the dexamethasone group, sirtinol group 2 and sirtinol group 3 (P < 0.05). However, there was no significant difference among dexamethasone group, sirtinol groups 2, and sirtinol group 3 (P > 0.05). The interleukin-5 content in the bronchoalveolar lavage fluid was lowest in the blank control group and highest in the asthma group. The interleukin-5 content in the sirtinol group 4 was significantly higher than that in the sirtinol group 2, 3, and dexamethasone group (P < 0.05). However, there was no significant difference among the dexamethasone group, sirtinol group 2, and sirtinol group 3 (P > 0.05). To conclude, both dexamethasone and sirtinol can reduce the expression level of SIRT1 and the content of interleukin-5, and relieve airway inflammation in asthmatic mice. They have similar effects, but the effect of the latter is related to the concentration. 
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    Inducing macrophage polarization to M2 anti-inflammatory type reduces oxidative damage in diabetic retinopathy mice
    Yin Liang, Zhang Mingxue, Li Jianan, Jiang Feng
    2022, 26 (17):  2685-2689.  doi: 10.12307/2022.535
    Abstract ( 397 )   PDF (899KB) ( 39 )   Save
    BACKGROUND: One of the main signs in diabetic retinopathy is the continuous formation of new blood vessels, and tumor necrosis factor ligand superfamily member 15 (TNFSF15), as an angiogenesis inhibitor, can significantly inhibit angiogenesis.
    OBJECTIVE: To investigate the mechanism by which TNFSF15 reduces oxidative damage in diabetic retinopathy mice by inducing macrophage polarization to M2 anti-inflammatory type. 
    METHODS: Forty male CD-1 mice were randomly divided into four groups (n=10 per group): a normal group, a model group, a TNFSF15 group, and a vascular endothelial growth factor group. Except for the normal group, a diabetic retinopathy model was established in all the groups by using streptozotocin and fundus angiography respectively. After the success of the modeling, mice in the TNFSF15 group were intraperitoneally injected with 250 mg/L TNFSF15, and mice in the vascular endothelial growth factor group were intraperitoneally injected with 250 mg/L vascular endothelial growth factor. Mice in the normal group and the model group were given the same volume of normal saline simultaneously. After the experiment was completed, the mouse retina was taken, and macrophages were extracted for in vitro culture. The cells were cultured with TNFSF15 in observation group or with phosphate buffered saline in control group. Hematoxylin-eosin staining was used to detect the pathological morphology of mouse omentum. Enzyme linked immunosorbent assay was used to detect serum levels of TNFSF15, vascular endothelial growth factor, malondialdehyde, and superoxide dismutase. Western blot was used to detect the protein expression of inducible nitric oxide synthase, Ym1, CD206, and CD163 in mouse retinal tissue. In vitro macrophage polarization to M2 anti-inflammatory type was also observed. This study protocol was approved by the Experimental Animal Ethics Committee of Tianjin Medical University (approval No. TJYKDX2021025).
    RESULTS AND CONCLUSION: Compared with the normal group, the blood glucose level and 24-hour urine volume, the serum level of vascular endothelial growth factor and malondialdehyde, and the protein expression of inducible nitric oxide synthase in retinal macrophages were significantly increased in model group (P < 0.05). While the above indicators in the TNFSF15 group were significantly lower than those in the model group (P < 0.05), and those in the vascular endothelial growth factor group were significantly higher than those in the TNFSF15 group (P < 0.05). Compared with the normal group, the body mass, serum levels of TNFSF15 and superoxide dismutase, and protein expression of YM1, CD206 and CD163 were significantly decreased in the model group (P < 0.05), while the above indicators in the TNFSG15 group were significantly higher than those in the model group (P < 0.05), and these indicators in the vascular endothelial growth factor group were significantly lower than those in the TNFSF15 group (P < 0.05). The mouse retina in the normal group had normal structure that was in alignment, and obvious retinal lesions were observed in the model group and vascular endothelial growth factor group. Compared with the model group and vascular endothelial growth factor group, there were fewer new blood vessels in the TNFSR15 group and its retinal structure intended to be normal. In the cell experiment, the protein expression of Ym1, CD206, and CD163 was increased significantly in the observation group compared with the control group (P < 0.05). Therefore, TNFSF15 may reduce oxidative damage in diabetic retinopathy mice and improve retinopathy by inducing macrophage polarization to M2 anti-inflammatory type.
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    Low-load compression training of the extremities influences surface electromyography and isokinetic flexor and extensor strength of core muscles
    Chen Keyi, Wang Dingxuan, Zhang Mengyao
    2022, 26 (17):  2744-2748.  doi: 10.12307/2022.545
    Abstract ( 413 )   PDF (1478KB) ( 49 )   Save
    BACKGROUND: Low-load compression training of the extremities can produce muscle hypertrophy in the extremities, but whether the training can exert a positive effect on the core muscles is rarely reported.
    OBJECTIVE: To explore the effects of low-load compression training of the extremities on the surface electromyography and isokinetic flexor and extensor strength of core muscles, aiming to provide theoretical basis for sports rehabilitation training for people who need to improve core muscle strength.
    METHODS: Sixteen college students were divided into a compression group (n=8) and a control group (n=8) according to a random number table. In the compression group, three sessions of five training actions with 25% 1RM were performed under the condition of extremity compression. Low-load training was performed in the control group. After 7 weeks, the changes in surface electromyography and isokinetic muscle strength were compared between two groups. The study protocol complied with the Declaration of Helsinki and the relevant ethical requirements of Chengdu Sport University. Each subject was voluntary to participate in the trial and fully informed of the trial process.
    RESULTS AND CONCLUSION: After trunk flexion training, the root mean square of surface electromyography signal of the rectus abdominis and external oblique muscles in the compression group was significantly different from those before training as well as those in the control group after training (P < 0.05). After trunk stretching training, the root mean square of surface electromyography signal of the erector spinae and multifidus muscles in the compression group was significantly different from those before training and those in the control group after training (P < 0.05). After standing leg stretching training, the root mean square of surface electromyography signal of the erector spinae and multifidus in the compression group was significantly different from those before training and those in the control group after training (P < 0.05). After bench press and sitting knee extension training, there was no significant difference in the root mean square of surface electromyography signal of core muscle groups (P > 0.05). In the compression group, the trunk flexor and extensor peak torque tests at the test angles of 30, 90 and 120 (°)/s were significantly different from those before training (P < 0.05). To conclude, the 7-week regular low-load compression training of the extremities can build the core muscles.
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    Effects of knee sleeve on perceived pain and lower extremity kinematics and kinetics in male and female runners with patellofemoral pain
    Yang Chen, Feng Ru, Zhou Zhipeng, Wan Xianglin, Qu Feng
    2022, 26 (17):  2749-2755.  doi: 10.12307/2022.546
    Abstract ( 429 )   PDF (769KB) ( 76 )   Save
    BACKGROUND: Knee sleeve is generally applied to prevent and treat patellofemoral pain in runners, while the intervention effects are still unclear.
    OBJECTIVE: To determine the effects of knee sleeve on perceived pain, lower extremity kinematics and kinetics in runners of different sexes with patellofemoral pain.  
    METHODS: Eleven male and nine female runners with patellofemoral pain were recruited as the participants. Each participant performed the biomechanical tests with and without a patellar-stabilizing knee sleeve. Perceived pain was evaluated by a visual analogue scale. Kinematics and kinetics data during running were collected using a motion capture system and synchronized force platforms. The study protocol was approved by the Sports Science Experimental Ethics Committee of Beijing Sport University, with an approval No. 2020021H. All the participants were volunteers for this trial and fully informed of the trial process.
    RESULTS AND CONCLUSION: When running with a knee sleeve, visual analogue scale scores were lower than those without a knee sleeve in both males and females (P < 0.01). When running with a knee sleeve, peak knee flexion angle in the landing phase was less than that without a knee sleeve in females (P < 0.01); however, there was no significant difference in males with or without a knee sleeve (P > 0.05). When running with a knee sleeve, peak hip adduction angle in the landing phase was less than that without a knee sleeve in both males and females (P < 0.01). When running with a knee sleeve, peak knee abduction (P < 0.01) and external rotation moments (P < 0.01) in the landing phase were higher than those without a knee sleeve in both males and females. In conclusion, the use of knee sleeve can alleviate perceived pain in both male and female runners who suffer from patellofemoral pain; reduce the peak knee flexion angle and hip adduction angle in female runners with patellofemoral pain, and reduce the peak hip adduction angle in male runners with patellofemoral pain, indicating a sex-specific effect of knee sleeve on lower extremity kinematics; and increase the peak knee abduction and external rotation moments in both male and female runners with patellofemoral pain, indicating  the use of knee sleeve may increase the knee joint loading.  
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    Bone morphogenetic protein 7 inhibits apoptosis of nucleus pulposus cells
    Xu Xuezhen, Song Lixian, Li Aiqun, Yang Jian, Li Xiaokun, Wang Zhanqing, Shi Qingpeng
    2022, 26 (17):  2726-2731.  doi: 10.12307/2022.542
    Abstract ( 344 )   PDF (770KB) ( 29 )   Save
    BACKGROUND: Disc degeneration is one of the major causes of lower back pain, and current clinical surgical treatments can relieve painful symptoms but sacrifice disc function and cannot completely cure disc degeneration. Therefore, it is important to develop new biological treatments to curb the progression of early disc degeneration, or to regenerate degenerated disc tissue.
    OBJECTIVE: To investigate whether bone morphogenetic protein 7 can reduce the senescence of human nucleus pulposus cells during subculture and its possible mechanism. 
    METHODS: Patients who underwent discectomy were enrolled in this study. During the operation, the intervertebral disc tissue was obtained and human nucleus pulposus cells were extracted and subcultured in vitro for six times. The cells were then cultured with bone morphogenetic protein 7 or LY294002, a specific inhibitor of phosphatidyl-inositol 3-kinase. Cell proliferation ability, telomerase activity, β-galactosidase activity, and the expression of apoptosis-related genes and phosphatidyl-inositol 3-kinase/protein kinase B signaling pathway molecules were detected. 
    RESULTS AND CONCLUSION: Bone morphogenetic protein 7 could significantly increase the cell proliferation and telomerase activity of nucleus pulposus cells, decrease the activity of β-galactosidase, down-regulate the expression of p16 and p53, and activate phosphatidyl-inositol 3-kinase/protein kinase B signaling pathway. In addition, LY294002 could significantly reverse the anti-apoptotic effect of bone morphogenetic protein 7 on nucleus pulposus cells. Overall, bone morphogenetic protein 7 exerts the anti-apoptotic effect on nucleus pulposus cells by activating the phosphatidyl-inositol 3-kinase/protein kinase B signaling pathway. The results of this study can provide new knowledge for in vitro culture and tissue engineering of allogenic nucleus pulposus cells.
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    Effects of nuclear factor of activated T cells 5 on migration, invasion and cell cycle of human gastric cancer MGC803 cells
    Guo Junfu, Gao Xia, Chang Jiarong, Gao Shiqi, Miao Lanying
    2022, 26 (17):  2732-2737.  doi: 10.12307/2022.543
    Abstract ( 405 )   PDF (863KB) ( 89 )   Save
    BACKGROUND: Recent studies have shown that high expression of nuclear factor 5 of activated T cells (NFAT5) is closely related to the occurrence and progression of a variety of tumors. Previous studies have found that NFAT5 can promote the proliferation and inhibit the apoptosis of human gastric cancer MGC803 cells. 
    OBJECTIVE: To investigate the effects of NFAT5 on migration, invasion and cell cycle of human gastric cancer MGC803 cells. 
    METHODS: There were two groups: NC-siRNA and NFAT5-siRNA. The siRNAs were transfected to silence NFAT5 gene expression in MGC803 cells. Cell scratch assay, Transwell assay and flow cytometry were performed to test migration ability, invasion ability, and cell cycle distribution, respectively. 
    RESULTS AND CONCLUSION: The wound healing capacity of NC-siRNA group was significantly higher than that in the NFAT5-siRNA group. The number of cells passed through the ventricle in the NFAT5-siRNA group was obviously less than that in the NC-siRNA group [(134.63±25.62) vs. (195.00±60.41), P < 0.05]. Compared with the NC-siRNA group, the proportion of G1-phase cells was significantly increased [(60.03±0.55)% vs. (62.46±0.73)%, P < 0.05] and the proportion of S-phase cells was significantly decreased [(28.24±1.16)% vs. (25.44±1.15)%, P < 0.05]. Therefore, NFAT5 silencing in human gastric cancer MGC803 cells can inhibit cell migration and invasion abilities in vitro and change the cell cycle distribution, thereby reducing cell proliferation ability. NFAT5 is expected to be a new diagnostic and therapeutic target for gastric cancer.
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    Construction of pgaABCD gene deletion and complementation strains and properties of biofilm formation ability for Escherichia coli
    Gong Haiyan, Cheng Qian, Zhao Zhilong, Shi Yang
    2022, 26 (17):  2738-2743.  doi: 10.12307/2022.544
    Abstract ( 559 )   PDF (1135KB) ( 89 )   Save
    BACKGROUND: Escherichia coli can cause difficult refractory infections, which seriously threaten human health, due to the formation of “biofilms.” The pgaABCD opero is one of the important regulatory genes for biofilm formation.
    OBJECTIVE: To construct gene deletion strain MG1655/Δpga of Escherichia coli, construct the complementation strains of Δpga/pgaA, Δpga/pgaB, Δpga/pgaC, Δpga/pgaD by complementing pgaA, pgaB, pgaC and pgaD, respectively, observe the biofilm formation ability, and exopolysaccharide and morphological characteristics of deletion and complementation strains, and analyze the effects of gene pga on the regulation and characteristics of biofilm. 
    METHODS: Based on the Lambda Red recombination system, helper plasmid pKD46 was transferred into competent cells MG1655 to obtain MG1655/pKD46 monoclones. Targeting fragment of pgaABCD gene was transformed to competent cells MG1655/pKD46 to construct gene deleted mutant of MG1655/Δpga. Using plasmid pBR322 as vector, pBR322-pgaA, pBR322-pgaB, pBR322-pgaC, and pBR322-pgaD were constructed and transformed into MG1655/Δpga to obtain the corresponding complementation strains. Congo red-broth agar plate, crystal violet semi-quantitative method, and transmissionelectronmicroscopy were utilized to detect property changes of biofilm formation capacity of construction strains. At the same time, extracellular polysaccharide was detected using phenol-sulfuric acid method. 
    RESULTS AND CONCLUSION: The biofilm formation capacity and extracellular polysaccharide of deletion strains were significantly decreased (P < 0.05). Some cells were damaged and collapsed. The section showed vacuolardegeneration in bacteria. To conclude, deletion of gene pgaABCD can affect the biofilm characteristics for Escherichia coli, and the genes pgaA, pgaB, pgaC and pgaD, but not the only regulatory gene, are involved in the biofilm formation.
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    Virtual reality training improves motor function of the upper limbs in stroke survivors: an evaluation using transcranial magnetic stimulation
    Xiao Xiang, Huang Dongfeng
    2022, 26 (17):  2756-2761.  doi: 10.12307/2022.547
    Abstract ( 605 )   PDF (811KB) ( 165 )   Save
    BACKGROUND: Motor deficits of the upper limbs after stroke may be related to a reduction in neural drive from the cortex to muscles.  
    OBJECTIVE: To explore the mechanism by which virtual reality training acts on the upper limb motor function of stroke patients based on the motor evoked potentials triggered by transcranial magnetic stimulation and changes in clinical indications.
    METHODS: Thirty stroke patients were recruited and randomized into two groups: an experimental group and a control group, followed by 4 weeks of virtual reality training using Kinect somatosensory interaction technology and occupational therapy, respectively. Two assessments involving Fugl-Meyer upper-extremity score, transcranial magnetic stimulation-induced motor evoked potential and game score were conducted before and after intervention. 
    RESULTS AND CONCLUSION: The Fugl-Meyer upper-extremity score presented no significant difference between two groups before intervention (P > 0.05), and a significant improvement in the two groups after intervention (P < 0.05). The Fugl-Meyer upper-extremity score presented a greater improvement in the experimental group compared with the control group after intervention (P < 0.05). Game scores reflected that motion performance of each participant in the experimental group improved. Transcranial magnetic stimulation assessment showed that cortex latency and central motor conduction time were significantly reduced in the experimental group compared with the control group (P < 0.05). Whereas, there was no significant difference in the amplitude of motor evoked potential between two groups after intervention. To conclude, the virtual reality training can improve the motor function of the upper limbs in patients after stroke, which may be realized by facilitating the reconstruction of nerve conduction pathway. 
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    Blood flow restriction method for inducing cross-education phenomenon and muscle function reconstruction
    Wang Yongchao, Wang Baochen, Wei Zhuying, Bao Chunyu, Liu Shijun, Meng Qinghua
    2022, 26 (17):  2762-2767.  doi: 10.12307/2022.548
    Abstract ( 495 )   PDF (787KB) ( 87 )   Save
    BACKGROUND: Cross-education phenomenon and blood flow restriction have been studied in the field of sports rehabilitation. However, the traditional resistance training still occupies the dominant position in the induction of cross-education phenomenon, and blood flow restriction method derived from it has received little attention. Several studies have confirmed that blood flow restriction has a significant inducing effect on cross-education phenomenon, but no comparative experiment has been found on the effect of traditional resistance training versus blood flow restriction on cross-education phenomenon.
    OBJECTIVE: To explore the generating mechanism of cross-education phenomenon and the mechanism of blood flow restriction, and to explore the greater benefits and wider clinical application of blood flow restriction in inducing cross-education phenomenon.
    METHODS: The first author searched for relevant literature in the Web of Science, PubMed, and EMbase, analyzed and summarized relevant high-quality articles for final review. 
    RESULTS AND CONCLUSION: Low-load blood flow restriction resistance training is a unique alternative to non-blood flow restriction resistance training, which can induce greater neuromuscular adaptability under less mechanical stress and exercises. Blood flow restriction can be used as a new exercise scheme to reduce muscle strength and muscle loss after rehabilitation and during limb fixation. Meanwhile, blood flow restriction also provides a unique mechanism, which can be used alone or combined with exercise to potentially increase the muscle strength and muscle mass of the contralateral untrained limb. The most important conduction pathway of cross-education phenomenon is carried by the nervous system, the recruitment of motor units by blood flow restriction training is accelerated and improved, and the higher neuromuscular adaptability is stimulated by local higher metabolic pressure, all of which make blood flow restriction training a more efficient prerequisite for inducing cross-education phenomenon. At present, due to the limited sample size and the lack of a clear definition of pressure scope in blood flow restriction training, there are still many problems to be solved in the practical application of blood flow restriction-cross-education, including the range of pressure used in clinical application, the different responses of patients at different ages to different pressures, and how to urge patients to complete the whole cycle of rehabilitation training under the pain of training. In the future, strengthening the exploration of cross-education phenomenon induced by blood flow restriction will make a larger breakthrough in the clinical application of cross-education phenomenon.
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    Benefit and physiological mechanism of low-intensity resistance training with blood flow restriction intervention on muscle fitness
    Yu Wei, Song Gang, Liu Yiwen
    2022, 26 (17):  2768-2774.  doi: 10.12307/2022.549
    Abstract ( 515 )   PDF (852KB) ( 74 )   Save
    BACKGROUND: Blood flow restriction (also known as pressure training) combined with low-intensity resistance training has been proved to promote muscle adaptation in different populations. However, it is unclear about how this training method affects the muscle fitness and related mechanism of subjects, because of the different methods.
    OBJECTIVE: To review the application and possible mechanism of blood flow restriction combined with low-intensity resistance training in promoting muscle hypertrophy and muscle strength growth, so as to provide some useful references for sports science researchers, coaches and athletes in future research or training practice.
    METHODS: Relevant literatures were searched in Web of Science, Index Medicus, EMBASE, CNKI and other databases, with “blood flow restriction training, pressure training, resistance training, training volume, training frequency, interval time, muscle fitness, muscle hypertrophy, low intensity training, muscle metabolism” as keywords in English and Chinese, respectively. The search deadline was March 1, 2021. According to the inclusion and exclusion criteria, 63 typical literatures were finally obtained.
    RESULTS AND CONCLUSION: Blood flow restriction training can cause tissue hypoxia and pH decrease in the process of exercise, promote the secretion of growth hormone and mTOR pathway activation, increase the muscle synthesis, and improve the effect of lateral migration. It can not only improve the muscle fitness of the compression part, but also enhance the muscle strength and cross-sectional area of the non-compression muscle group, and avoid the risk of injury caused by high-intensity resistance training. There is a dose matching effect of exercise prescription in the effect of blood flow restriction training, that is, the matching between the degree of blood flow restriction (50-250 mmhg) and low-intensity resistance (20%-50%1RM). The best training effect can be obtained by considering the width of pressure band, pressure position, training amount, frequency and interval time. Low-intensity resistance training prescription may be a better alternative training method for the elderly or the injured rehabilitation population including athletes. However, there is a lack of research on this aspect as yet. To conclude, low-intensity resistance training (20%-50%1RM) combined with blood flow restriction can promote muscle hypertrophy and increase muscle strength, and the effect is similar to that of high-intensity resistance training. However, for subjects of different ages and different physical fitness levels, especially for those with physical defects, more data from further studies are needed to clarify the training effect and possible risks of low-intensity resistance training.
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    Sequence of prevention for anterior cruciate ligament injury: screening, intervention and assessment
    Yuan Haoxiang, Xu Jing, Zeng Jinshu, Chen Hao, Yan Yelei, Chen Jiahao, Liu Qingshan, Xu Fei
    2022, 26 (17):  2775-2781.  doi: 10.12307/2022.550
    Abstract ( 459 )   PDF (898KB) ( 75 )   Save
    BACKGROUND: Anterior cruciate ligament (ACL) injury is one of the common sports injuries in athletes and is affected by many factors. Injuries can lead to short-term physical function limitations and long-term sequelae, and all patients face a high risk of osteoarthritis after an anterior cruciate ligament injury. “Prevention” is an optimal choice at this stage.
    OBJECTIVE: Under the framework of the “Sequence of Prevention” model, to comprehensively review the prevention of anterior cruciate ligament injury and to preliminarily construct a programmatic prevention process for anterior cruciate ligament injury.
    METHODS: A systematic review of the literature was undertaken from January 1, 2000 to December 31, 2020 using the following databases: PubMed, Embase, Google Scholar, Web of Science, and SPORTDiscuss. Finally 68 articles were included for further review. The procedure incorporates determining the mechanism of injury, identifying injury risk factors, screening high-risk athletes, formulating the prevention plans and assessments of anterior cruciate ligament injury, so as to establish a comprehensive understanding of the prevention of anterior cruciate ligament injury.
    RESULTS AND CONCLUSION: There are many research methods that focus on the mechanism of anterior cruciate ligament injury. A current research paradigm of “knee joint finite element model” simulation integrates the advantages of in vivo, in vitro and computer research, and provides new ideas for future specific individual research. The etiological factors of anterior cruciate ligament injury are more complicated, but comprehensive neuromuscular control training can effectively improve the abnormal biomechanical properties of individuals. Especially for pre-pubertal women, it may also induce the phenomenon of “neuromuscular spurt.” Therefore, comprehensive neuromuscular control training is recommended to be included in the curriculum for children as soon as possible to reduce the risk of injury. This review compiles several sets of relatively mature prevention training programs, among which FIFA11+ is the most popular pre-football warm-up program at this stage. However, the specificity of these programs for the prevention of individuals of different ages, sports events and specific injury risks needs to be further studied. A research team has developed a risk scoring tool based on the “nomogram”, the “landing hazard scoring system”, the “tuck jump evaluation” and the “QASLS scoring system,” including quantitative and qualitative evaluation methods, which are easy to operate and has low cost. These tools can be used for large-scale screening and real-time evaluation of training effects, and also point out the direction for the future development of screening and evaluation tools in various high-risk sports scenarios.
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    Effect of estrogen on bone remodeling and root resorption during orthodontics
    Cheng Yi, Liu Ting, Guo Yujing, Sun Xiaotong, Bi Lan, Zhang Ronghe
    2022, 26 (17):  2782-2788.  doi: 10.12307/2022.551
    Abstract ( 494 )   PDF (713KB) ( 63 )   Save
    BACKGROUND: Orthodontic tooth movement and orthodontic induced root resorption are an important part of orthodontic treatment. Estrogen can regulate the rate of orthodontic tooth movement by influencing the bone remodeling of periodontal tissue, thereby inhibiting orthodontic-induced root resorption.
    OBJECTIVE: To review the mechanism of estrogen underlying orthodontic tooth movement and orthodontic induction of root resorption.
    METHODS: The first author searched PubMed, CNKI, and WanFang databases using the keywords of “estrogen; orthodontic tooth movement; orthodontically induced root resorption; osteoclast; osteoblast; bone marrow mesenchymal stem cells; periodontal ligament stem cells” in English and Chinese, respectively. Finally, 53 articles were included for further review. 
    RESULTS AND CONCLUSION: Orthodontic tooth movement is an important part of orthodontic treatment. It can be achieved through bone reconstruction under mechanical force, and alveolar bone reconstruction is the basis of orthodontic tooth movement. Estrogen acts as an important regulator of bone tissue remodeling. Estrogen inhibits osteoclast differentiation, prolongs the life span of osteoclasts, promotes the proliferation, differentiation and function of osteoblasts through a variety of pathways and multiple cytokines, thereby inhibiting bone resorption, promoting bone formation, reducing bone remodeling, and inhibiting orthodontic tooth movement. Estrogen may reduce orthodontics-induced dental root resorption by inhibiting cementoclasts. The differentiation of osteoclasts and odontoclasts is of great significance in the process of tooth movement and root resorption. Recent studies have found that tyrosine kinase acts as an important signal medium for estrogen to inhibit the differentiation, survival and function of human osteoclasts. Although preliminary studies on the role of estrogen in bone remodeling and tooth root resorption have been reported, which mechanism exerts the dominant role has not been elucidated, and most of them are at the stage of basic or animal research. Research on relevant mechanisms and clinical research on this aspect are still needed.
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