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    08 June 2020, Volume 24 Issue 16 Previous Issue    Next Issue
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    Lateral versus anterior open injectors in the percutaneous vertebroplasty treatment of osteoporotic vertebral compression fractures 
    Pang Jutao, Chen Hong, Liu Bin, Zhang Wei, Sun Jianhua, Zhou Lianjun, Zhang Xinhu
    2020, 24 (16):  2461-2466.  doi: 10.3969/j.issn.2095-4344.2268
    Abstract ( 454 )   PDF (25448KB) ( 34 )   Save

    BACKGROUND: Studies have shown that lateral open injectors can improve the cement filling pattern in percutaneous vertebroplasty, direct cement flow into the vertebral body, reduce the risk of leakage, and increase the amount of bone cement injected compared with conventional anterior open injectors.

    OBJECTIVE: To investigate the clinical efficacy of lateral open injectors in the percutaneous vertebroplasty treatment of osteoporotic vertebral compression fractures and its effect on preventing intraoperative cement leakage.

    METHODS: A total of 220 patients with osteoporotic vertebral compression fractures admitted at Harrison International Peace Hospital from January 2014 to December 2018 were enrolled. Of these, 114 patients underwent bilateral pedicle percutaneous vertebroplasty with the lateral open injector, and 106 patients underwent bilateral pedicle percutaneous vertebroplasty with standard anterior open injector. X-ray and CT scans were performed to evaluate bone cement leakage. The Visual Analogue Scale score and vertebral compression rate were evaluated at baseline, postoperative 3 days and 6 months. The study was approved by the Ethics Committee of Harrison International Peace Hospital (approval No. 20131214841X).

    RESULTS AND CONCLUSION: (1) All the 220 patients successfully completed the operation without any early complications, the pain was alleviated, and the quality of life was significantly improved. (2) The amount of bone cement injected in the lateral open injector group was higher than that in the anterior open injector group (P < 0.05). (3) The Visual Analogue Scale scores at 3 days and 6 months postoperatively were significantly lower than those at baseline (P < 0.05). There was no significant difference in the Visual Analogue Scale score between two groups (P > 0.05). (4) Twenty-one vertebral bodies in 130 vertebrae in the lateral open injector group showed cement leakage (leakage rate of 16.15%). Bone cement leakage (leakage rate of 30%) occurred in 36 out of 120 vertebral bodies in the anterior open injector group. So the leakage rate of cement in the lateral open injector group was lower than that in the anterior open injector group (P < 0.05). (5) The vertebral compression rate at 3 days and 6 months postoperatively in the two groups was significantly lower than that at baseline (P < 0.05). There was no significant difference in vertebral compression rate between two groups (P > 0.05). (6) These results imply that the use of the lateral open or anterior open injector for bone cement injection for percutaneous vertebroplasty for treatment of osteoporotic vertebral fractures can achieve satisfactory clinical outcomes. However, a lateral open injector can optimize bone cement injection mode, reduce the potential risk of leakage and infiltration into the blood vessels around the vertebral body, and adjust the direction of bone cement injection to achieve a satisfactory bone cement filling effect.

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    Relationship between unilateral percutaneous kyphoplasty for treating Kummell’s disease and the amount of injected bone cement
    Ren Yide, Zhang Yafeng, Li Feng, Gao Hongwen
    2020, 24 (16):  2467-2472.  doi: 10.3969/j.issn.2095-4344.2252
    Abstract ( 344 )   PDF (26513KB) ( 54 )   Save

    BACKGROUND: Percutaneous kyphoplasty is an effective method to treat Kummell’s disease, but there is no uniform standard for the amount of injected bone cement.

    OBJECTIVE: To investigate the relationship between unilateral percutaneous kyphoplasty for treating Kummell’s disease and the amount of injected bone cement.

    METHODS: Totally 35 cases of Kummell’s disease, who were treated in the Wuxi Hospital of Traditional Chinese Medicine from January 2014 to June 2018, were included in this study, including 11 males and 24 females. According to bone cement injection volume, unilateral percutaneous kyphoplasty was performed in two groups: Low volume group (n=16; volume ≤ 3 mL) and conventional quantity group (n=19;  3 mL ≤ volume ≤ 6 mL). The leakage of bone cement was observed during operation. Vertebral body refracture was postoperatively observed. Visual analogue scale and Oswestry dysfunction index were used to evaluate the efficacy of the surgery preoperatively, 2 days postoperatively and at last follow-up. Vertebral kyphotic Cobb’s angle and the height of injured vertebral anterior edge were assessed by imaging. This study was approved by the Ethics Committee of Wuxi Hospital of Traditional Chinese Medicine.

    RESULTS AND CONCLUSION: (1) All patients successfully completed the operation, and were followed up for 6-36 months. (2) Visual analogue scale scores and Oswestry dysfunction index of the two groups 2 days after treatment and at final follow-up were significantly lower than those before surgery (P < 0.05). However, there was no significant difference in visual analogue scale scores and Oswestry dysfunction index between the two groups (P > 0.05). (3) Cobb’s angle of vertebral kyphosis and the height of the anterior edge of injured vertebral bodies were significantly improved in the two groups 2 days after treatment and at final follow-up (P < 0.05), but there was no significant difference between the two groups (P > 0.05). (4) In the conventional quantity group, cement leakage occurred in 5 cases and vertebral body refracture occurred in 2 cases. In the low volume group, cement leakage occurred in 1 case and vertebral body refracture occurred in 2 cases. The incidences of bone cement leakage and vertebral body refracture had no significant difference between the two groups (P > 0.05). (5) The results showed that unilateral percutaneous kyphoplasty could effectively relieve pain with different amounts of bone cement in Kummell’s disease, and there was no difference in leakage rate and safety of bone cement.

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    Correlation of percutaneous vertebroplasty effect on osteoporotic vertebral compression fracture with injection amount and dispersion degree of bone cement
    Wu Haibo, Yu Zhijun, Bai Manmo
    2020, 24 (16):  2473-2477.  doi: 10.3969/j.issn.2095-4344.2241
    Abstract ( 398 )   PDF (24068KB) ( 134 )   Save

    BACKGROUND: Previous studies show that the amount and diffusion degree of bone cement in vertebroplasty have some influence on the postoperative recovery of patients with osteoporotic vertebral compression fracture, but there are few reports about the correlation between the amount and diffusion degree of bone cement in vertebroplasty and the recovery of vertebral body.

    OBJECTIVE: To investigate the relationships between the effect of percutaneous vertebroplasty on osteoporotic vertebral compression fractures and the injection amount and dispersion degree of bone cement.

    METHODS: Totally 102 osteoporotic vertebral compression fracture patients (109 vertebrae) who received treatment in the Sanya Hospital of Traditional Chinese Medicine from January 2017 to August 2018, including 42 males and 60 females at the age of 52-76 years, were retrospectively analyzed. All patients received percutaneous vertebroplasty. According to the injection amount of bone cement, they were divided into two groups: observation group 1 (injection > 4 mL, n=57) and control group 1 (injection ≤ 4 mL, n=45). According to the degree of dispersion of bone cement, they were divided into two groups: observation group 2 (filling rate > 15%, n=61) and control group 2 (filling rate ≤ 15%, n=41). Visual analogue scale score, Oswestry disability index, anterior vertebral height, Cobb angle, and the occurrence of cement leakage were observed before and after surgery. The correlations of the injection amount and dispersion degree of bone cement with the height of vertebral body recovered were analyzed. This study was approved by the Medical Ethics Committee of Sanya Hospital of Traditional Chinese Medicine.

    RESULTS AND CONCLUSION: (1) The visual analogue scale score and Oswestry dysfunction index of patients in the observation group 1 and control group 1 at 3 days after operation were decreased compared with before operation (P < 0.05), while those in the observation group 1 were lower than those in the control group 1 (P < 0.05). The visual analogue scale score and Oswestry disability index were decreased in the observation group 2 and control group 2 at 3 days after operation compared with before operation (P < 0.05), while those of the observation group 2 were lower than those of the control group 2 (P < 0.05). (2) The anterior height of vertebral body and the Cobb angle in the observation group 1 and control group 1 at 3 days after operation were improved than those before operation (P < 0.05), while those in observation group 1 were better than those in control group 1 (P < 0.05). The anterior height of vertebral body and the Cobb angle in observation group 2 and control group 2 at 3 days after operation were improved than those before operation (P < 0.05), while those in observation group 2 were better than those in control group 2 (P < 0.05). (3) There was no significant difference in the incidence of cement leakage between observation group 1 and control group 1 (P > 0.05). There was no significant difference in the incidence of cement leakage between observation group 2 and control group 2 (P > 0.05). (4) The height of vertebral body recovery was positively correlated with the injection amount and dispersion degree of bone cement (P < 0.05). (5) The results suggest that increases of the injection amount and dispersion degree of bone cement properly can alleviate the pain, improve the mobility, correct the deformity of vertebral posterior concave, and restore the height of vertebral body of osteoporotic vertebral compression fracture patients. The injection amount and dispersion degree of bone cement are positively correlated with the recovery height of vertebral body.  

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    Effect of bone morphogenetic protein-7 combined with porous tantalum on chondrogenic differentiation and function of bone marrow mesenchymal stem cells
    Cui Yishuang, Lai Zhenquan, Hu Zhongling, Wang Qian, Zhang Hui, Guo Baowen, Li Qijia
    2020, 24 (16):  2478-2484.  doi: 10.3969/j.issn.2095-4344.2251
    Abstract ( 359 )   PDF (34134KB) ( 50 )   Save

    BACKGROUND: The establishment of coculture system combined with physical factors and scaffold materials and the induction of cytokines have become the focus of chondrogenic differentiation of bone marrow mesenchymal stem cells.

    OBJECTIVE: To observe the effect of bone morphogenetic protein 7 combined with porous tantalum on chondrogenic differentiation of bone marrow mesenchymal stem cells.

    METHODS: Bone marrow mesenchymal stem cells of Sprague-Dawley rats (provided by Beijing Huafukang Biology) were isolated and cultured. Group intervention: (1) in the experimental group, porous tantalum tablet was added, while in the control group, porous tantalum tablet was not added. At 5 days after culture, cell growth on the surface of porous tantalum tablet was observed by phalloidin staining. At 1, 3, 5, and 7 days after culture, CCK-8 method was used to detect cell proliferation. (2) Group A was added with chondrocyte inducer; group B with chondrocyte inducer and bone morphogenetic protein 7; group C with domestic porous tantalum material and chondrocyte inducer; group D with domestic porous tantalum material and chondrocyte inducer and bone morphogenetic protein 7. At 7, 14 and 21 days after culture, the levels of type II collagen, SRY type high mobility group protein and matrix metalloproteinase-13 secreted by cells in each group was detected by ELISA. Western blot assay was used to detect the expression of type II collagen, SRY type high mobility group protein and matrix metalloproteinase-13. This study was approved by the Animal Experimental Ethics Committee of North China University of Science and Technology.

    RESULTS AND CONCLUSION: (1) The phalloidin staining results showed that bone marrow mesenchymal stem cells grew well on and around the porous tantalum surface. (2) At 3 and 5 days after culture, the proliferation of bone marrow mesenchymal stem cells was slower in the experimental group than in the control group (P < 0.05). There was no statistical difference in cell proliferation between the two groups at 1 and 7 days (P > 0.05). (3) At 7, 14 and 21 days, the expression of type II collagen and SRY high mobility group protein increased gradually among groups A, B, C and D (P < 0.05). At 7 days, the expression of matrix metalloproteinase-13 decreased gradually among groups A, B, C and D (P < 0.05). At 14 days, matrix metalloproteinase-13 secretion of matrix in group A was highest compared with that in group B, group C and group D (P < 0.05), but there was no significant difference between groups B, C and D (P > 0.05). At 21 days, there was no significant difference among groups A, B, C and D (P > 0.05). (4) Western blot assay showed that at 7, 14 and 21 days after culture, the expression level of type II collagen and SRY high mobility group protein increased gradually in groups A, B, C and D (P < 0.05). At 7 days, the expression of matrix metalloproteinase-13 decreased gradually in groups A, B, C and D (P < 0.05). At 14 days, the expression of matrix metalloproteinase-13 was higher in group A than in groups C and D (P < 0.05), and higher in groups B and C than in group D (P < 0.05). At 21 days, the expression of matrix metalloproteinase-13 was higher in group A than in groups B, C and D (P < 0.05). No significant difference was found among groups B, C and D (P > 0.05). (5) The results showed that bone morphogenetic protein-7 combined with domestic porous tantalum could induce cartilage differentiation of bone marrow mesenchymal stem cells, facilitate the expression of type II collagen and SRY high mobility group protein, and inhibit the expression of matrix metalloproteinase-13.

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    Three-dimensional printed polylactic acid resin humerus combined with bioactive coating promotes osteoblast adhesion and increases antibacterial ability 
    Zhang Zhongyan, Li Yubo, Qi Tongning, Chang Tao
    2020, 24 (16):  2485-2492.  doi: 10.3969/j.issn.2095-4344.2255
    Abstract ( 339 )   PDF (33368KB) ( 45 )   Save

    BACKGROUND: Polylactic acid has good bio-toughness and biocompatibility, but bio-inertity limits the interaction of polylactic acid resin implants with surrounding tissues after implantation in vivo. Therefore, research on improving the biological activity of polylactic acid resin and improving bone binding properties has gradually become a hotspot of biological materials.

    OBJECTIVE: To observe the effects of polylactic acid resin combined with different bioactive coatings on the adhesion, proliferation and differentiation of osteoblasts, and to analyze their antibacterial ability.

    METHODS: The three-dimensional printed polylactic acid biomimetic tibia specimens were made, and chitosan-α-β-GP thermosensitive hydrogel coating and chitosan nanoparticle coating were prepared on the surface. MC3T3-E1 cells were inoculated separately into three-dimensional printed polylactic acid biomimetic tibia (blank group), chitosan-α-β-GP thermosensitive hydrogel coated three-dimensional printed polylactic acid biomimetic tibia (hydrogel group) and shell-containing coating three-dimensional printed polylactic acid biomimetic tibia (nanoparticle group) surface. The cell adhesion, proliferation, and differentiation were observed. The cell adhesion plaque and osteoprotegerin gene and protein expression levels, and the expression levels of p65 and p-p65 were detected. The interleukin-6 secretion was detected. Gram-positive and Gram-negative bacteria were inoculated on the surface of the three samples, respectively, and the bacterial adhesion was observed.

    RESULTS AND CONCLUSION: (1) After 8 hours of inoculation, the number of adherent cells in the nanoparticle group was higher than that in the hydrogel and blank groups (P < 0.05), and the number of adherent cells hydrogel group was higher than that in the blank group (P < 0.05).  (2) Cell viability in the nanoparticle and gel groups was higher than that in the blank group at 2, 4, 6 and 8 days (P < 0.05). (3) After 6 days of culture, the cell adhesion spots and the expression levels of osteoprotegerin protein and mPNA in the particle and hydrogel groups were higher than those in the blank group (P < 0.05), and they were higher in the nanoparticle group than those in the hydrogel group (P < 0.05). (4) After 8 days of culture, the alkaline phosphatase activity and the secretion content of interleukin-6 in the nanoparticle and hydrogel groups were higher than those in the blank group (P < 0.05), and they were higher in the nanoparticle group than those in the hydrogel group (P < 0.05). The level of p-p65 in the nanoparticle group was higher than that in the hydrogel group (P < 0.05), and it was higher in the hydrogel group than that in the blank group (P < 0.05). (5) The antibacterial abilities to Gram-positive and Gram-negative bacteria were as follows: nanoparticle group > hydrogel group > blank group (P < 0.05). (6) In summary, three-dimensional printed polylactic acid humerus combined with α-β-GP thermosensitive hydrogel and chitosan nanoparticles can effectively promote cell adhesion and proliferation and increase alkaline phosphatase activity, the secretion of antibacterial factors, and improve antibacterial ability, which is related to activation of NF-κB signaling pathway.

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    Properties of gelatin methacrylate/decellularized meniscus extracellular matrix composite hydrogel with different crosslinking densities
    Zhou Jian, Tian Zhuang, Tian Qinyu, Luo Xujiang, Peng Liqing, Li Kun, Sui Xiang, Huang Jingxiang, Liu Shuyun, Guo Quanyi, Yao Qi
    2020, 24 (16):  2493-2499.  doi: 10.3969/j.issn.2095-4344.2286
    Abstract ( 465 )   PDF (30026KB) ( 50 )   Save

    BACKGROUND: Crosslinked polymer chains have a remarkable effect on the fundamental properties and cytocompatibility of hydrogels, and crosslinking density can significantly change the formation of polymer chains. There are few studies on the effect of the properties of hydrogels caused by crosslinking density.

    OBJECTIVE: To prepare a composite hydrogel with a favorable cytocompatibility and to explore the effect of crosslinking density on the properties of the hydrogel.

    METHODS: Gelatin methacrylate solution was prepared, and decellularized meniscus extracellular matrix and LAP solution were added to prepare the pre-gel solution, which was crosslinked by blue ray. The crosslinking time was 10, 30 and 60 seconds. The compression elastic modulus, swelling ratio and degradability of hydrogels were detected. Meniscus fibrochondrocytes were added into the pre-gel solution, and crosslinked by blue ray. The cell viability, morphology and gathering were detected at 10, 30 and 60 seconds of crosslinking.

    RESULTS AND CONCLUSION: (1) The hydrogel with 60 seconds of cross-linking time had higher compression elastic modulus than that of the hydrogel with 10 and 30 seconds of cross-linking time (P < 0.05). (2) The swelling ratio of the hydrogel with 10 seconds of cross-linking time was significantly higher than that of the hydrogel with 30 and 60 seconds of cross-linking time (P < 0.05). The swelling ratio of the hydrogels with 30 versus 60 seconds of cross-linking time had no significant difference (P > 0.05). (3) With the crosslinking time increasing, the degradation time of hydrogels increased. The hydrogels with 60 seconds of cross-linking time degraded completely at 80 minutes, and hydrogels with 10 seconds of cross-linking time degraded completely at 50 minutes. (4) After 24 hours of culture, the cell viability in all groups was over 95% (P > 0.05). (5) At 1 day after culture, the cells were in sphere-shape and distributed evenly in all groups. On day 4, the cells in all groups began to extend, and there were small cell masses in the hydrogels with 10 seconds of cross-linking time. On day 7, the dendritic extension in all groups was obvious, and there were dominant cell masses in the hydrogels with 10 seconds of cross-linking time. (6) After 1, 7 and 14 days of culture, cell viability in all groups was over 85%. At 1 day after culture, the cells in the hydrogels with 10 seconds of cross-linking time were in sphere-shape and distributed evenly. On day 28, the cells extended in dendritic shape, and gathered in reticular formation. (7) In summary, the property of gelatin methacrylate/decellularized meniscus extracellular matrix composite hydrogel can be optimized by adjusting crosslinking density.

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    Efficacy and complications of different viscosities of high-dose bone cement applied in percutaneous vertebroplasty  

    Wang Mengran, Fu Zhiyi, Wang Huidong, Wu Yujie
    2020, 24 (16):  2500-2505.  doi: 10.3969/j.issn.2095-4344.2285
    Abstract ( 351 )   PDF (28201KB) ( 39 )   Save

    BACKGROUND: Percutaneous vertebroplasty has been extensively applied in the treatment of senile osteoporotic vertebral compression fracture with pain. However, the appropriate dose of bone cement remains controversial.

    OBJECTIVE: To compare the efficacy and complications of different viscosities of high-dose bone cement applied in the treatment of osteoporotic vertebral compression fractures by percutaneous vertebroplasty.

    METHODS: One hundred and sixty-nine patients with single-segment osteoporotic fractures at thoracolumbar level (T12-L2) admitted at Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine from February 2014 to December 2018 were included. All patients were treated by percutaneous vertebroplasty with high-dose (> 4 mL) bone cement at low viscosity (n=85, control group) and high viscosity (n=84, observation group). The Visual Analogue Scale score, anterior vertebral height, Cobb angle and bone cement leakage were recorded before and 2 days after surgery. The study was approved by the Medical Ethics Committee of Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, China (approval No. SH9H-2019-T90-1).

    RESULTS AND CONCLUSION: (1) The Visual Analogue Scale score at postoperative 2 days in both groups were significantly lower than that at baseline (P < 0.05), and there was no significant difference between the observation and control groups (P > 0.05). (2) The anterior vertebral height at postoperative 2 days in both groups was significantly higher than that at baseline (P < 0.05), and there was no significant difference between two groups (P > 0.05). (3) Compared with the baseline level, the Cobb angle at postoperative 2 days in both groups was significantly decreased (P < 0.05), and there was no significant difference between two groups (P > 0.05). (4) The incidence of bone cement leakage in the observation group (36/84, 42.9%) was significantly lower than that in the control group (57/85, 67.1%) (P < 0.05). The incidence of leakage in paravertebral vessels and spinal canal in the observation group was significantly lower than that in the control group (P < 0.05). (5)  Peri-implant infection, allergic reaction, immune and rejection reactions occurred in neither groups. (6) These results indicate that treatment of senile osteoporotic vertebral compression fractures with high dose of low- and high-viscosity bone cement can result in good clinical outcomes. However, the incidence of leakage is higher in the low-viscosity bone cement, and high-viscosity bone cement can significantly reduce the risk of leakage, especially the leakage of paravertebral blood vessels and spinal canal.

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    Differences in the effect of two injectable Pluronic F-127 hydrogel composites in repairing rabbit cartilage defects  
    Fan Xunqin, Zhang Mingyong, Dai Neng, Wang Zhemin, Liu Shuan
    2020, 24 (16):  2506-2512.  doi: 10.3969/j.issn.2095-4344.2254
    Abstract ( 448 )   PDF (29462KB) ( 48 )   Save

    BACKGROUND: Preliminary experiments show that bone marrow mesenchymal stem cells transfected with SOX9 gene can grow and proliferate in Pluronic F-127 hydrogel, promote the secretion of extracellular matrix, and increase the expression of cartilage matrix.

    OBJECTIVE: The SOX9 gene was transduced into bone marrow mesenchymal stem cells by lentivirus gene induction, and then combined with injectable Pluronic F-127 hydrogel to observe the effect of Pluronic F-127 hydrogel on repairing cartilage defects.

    METHODS: SOX9 gene was transfected into bone marrow mesenchymal stem cells by lentivirus gene induction. After 48 hours of transfection, SOX9 gene was combined with Pluronic F-127 hydrogel. Sixty New Zealand white rabbits provided by the Experimental Animal Center of Wuhan University of Science and Technology were selected to establish the models of femoral condylar cartilage defect of the right knee joint. The rabbits were randomly divided into three groups: model group without implantation of any material at the defect site, control group with implantation of non-transfected bone marrow mesenchymal stem cells and Pluronic F-127 hydrogel complex at the defect site, and experimental group with implantation of SOX9 gene-transfected bone marrow mesenchymal stem cells and Pluronic F-127 hydrogel complex at the defect site. Four and twelve weeks after operation, the defect tissues were taken for three-dimensional reconstruction of micro-CT, hematoxylin-eosin staining, Safranine O staining, type II collagen immunohistochemical staining and Wakitani soft tissue repair histological score. This study was approved by the Ethics Committee of Wuhan University of Science and Technology.

    RESULTS AND CONCLUSION: (1) At 12 weeks after operation, three-dimensional reconstruction of Micro-CT showed that there was no obvious repair in the defect area of the model group, and there was still a large depression in the center. In the control group, the central depression area was significantly reduced and more trabecular structures of regenerated bone were observed. In the experimental group, the defect area was basically repaired. (2) At 12 weeks after operation, hematoxylin-eosin staining showed that there was no trabecular bone structure, disordered cell distribution and no cartilage lacunae at the defect area of the model group. In the control group, more bone tissue was reconstructed, and the defect area was mainly filled with cartilage-like tissue and fibrous tissue. In the experimental group, bone tissue was reconstructed adequately, and the defect area was mainly filled with chondroid cells and chondroid extracellular matrix. Cells arranged columnarly, similar to the surrounding cartilage. (3) At 12 weeks after surgery, Safranine O staining and collagen II immunohistochemical staining results showed that a small amount of glycosaminoglycan was observed, but no type II collagen was found in the model group. The expression of glycosaminoglycan and type II collagen was more in the control group. The expression of glycosaminoglycan and type II collagen was highest in the experimental group compared with the other two groups. (4) The histological score of Wakitani soft tissue repair in the experimental group was higher than that in the control group and model group (P < 0.05). (5) The results suggested that Pluronic F-127 hydrogel complex loaded with SOX9 gene transfected bone marrow mesenchymal stem cells can promote the repair of cartilage defects.

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    Effects of the changes of thickness and placement position of rectangular attachment on canine tooth torsion correction
    Chen Zhouyan, Zhou Rong, He Song, Wu Dingdan, Wu Xi, Bai Rui, Huang Yue
    2020, 24 (16):  2513-2519.  doi: 10.3969/j.issn.2095-4344.2262
    Abstract ( 485 )   PDF (25425KB) ( 78 )   Save

    BACKGROUND: Using interproximal enamel reduction, adding attachments and over-correction are major methods to improve the efficiency of correcting tooth torsion when using clear aligners in the clinic. However, the choice and placement of attachments depend on the experience and habits of orthodontists, and whether the effects are different has not been reported.

    OBJECTIVE: To explore the effects of rectangular attachment with different thicknesses and locations on the left maxillary canine tooth torsion in clear aligner by three-dimensional finite element analysis.

    METHODS: The finite element models of the clear aligner-attachment-maxillary canine-periodontal ligament-spongy bone-cortical bone and the clear aligner-maxillary canine-periodontal ligament-spongy bone-cortical bone were established according to the scanning data of in vitro maxillary canine. The models with attachments were divided into four groups based on different thicknesses of attachment, namely 0.5, 0.75, 1.0, and 1.5 mm groups. The placement positions were divided into five areas: mesial, distal, occlusal, median, and gingival of canine. 2° clockwise rotation of the tooth axis (X axis) was applied to the clear aligner. The action of the appliance and the canine were calculated by MSC.Marc.Mentat software. Then, the nephograms of stress and displacement, and the maximum stress and displacement values were collected.

    RESULTS AND CONCLUSION: (1) Whether the rectangular attachment was used or not, the two models’ distribution of canine’s displacement and periodontal stress were the same. The stress values of periodontal ligament were all higher than those without rectangular attachment. (2) With the thickness of rectangular attachment increasing, the maximum displacement values of the canine increased gradually, which were 42.94, 49.32, 52.52 and 59.39 µm, respectively. (3) When the rectangular attachment was placed in different positions, the maximal displacement of canine teeth the attachment of which was placed on the median was almost the same with that of the gingival side. While the changes in the mesial and distal directions were irregular. (4) The use of rectangular attachments makes no effect on the movement of instant canines, which only plays a synergistic role in the control of canine tooth torsion. The thickness of the attachment has a certain effect on the torsion of appliance. When the thickness increases, the maximum displacement of the canine tooth and the stress of the periodontal ligament are increased. In the vertical direction, the closer of the placement is to the crown, the better the control of the rotated canine is.

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    Effect of glaze technology on adhesive and mechanical properties of yttria-stabilized tetragonal zirconia polycrystal ceramics
    Xu Xiaomin, Zhu Yanping, Chen Chunxia, Zhang Kai, Fan Hong
    2020, 24 (16):  2520-2525.  doi: 10.3969/j.issn.2095-4344.2275
    Abstract ( 608 )   PDF (25930KB) ( 33 )   Save

    BACKGROUND: Any surface treatments should improve the bond strength of yttria-stabilized tetragonal zirconia polycrystal ceramics without damaging the original strength. Currently, there is no information about the influence of glaze technology on the bond strength of yttria-stabilized tetragonal zirconia polycrystal ceramics, and its influence on the material strength is unclear.

    OBJECTIVE: To evaluate the effect of glaze technology on the mechanical behavior of yttria-stabilized tetragonal zirconia polycrystal ceramics and on the bond strength with resin cements.

    METHODS: Yttria-stabilized tetragonal zirconia polycrystal ceramics specimens were prepared and randomly divided into four groups: group A: the surface was not treated; group B: sandblasting with 110 μm Al2O3 particles; group C: glaze + hydrofluoric acid etching; group D: glaze + hydrofluoric acid etching + silanization. The surface morphology, surface roughness, phase transformation, elemental composition, shear bond strength and flexural strength of zirconia specimens after surface treatments were tested.

    RESULTS AND CONCLUSION: (1) The surface roughness of treatment groups increased obviously, whose descending order was group C (0.62±0.01) μm > group D (0.55±0.02) μm > group B (0.11±0.02) μm > group A (0.05±0.01) μm (P < 0.05). (2) The surface of specimens in the group B contained 2.2% monoclinic zirconia, while the content of other groups was zero. (3) In addition to elements of Zr and O, there was 6.49% Al element in the group B specimens, and 18.67% and 25.78% Si element in the groups C and D specimens, respectively. (4) The shear bond strength in the groups A, B, C and D was (3.11±0.40), (4.23±0.45), (6.62±0.60) and (10.46±0.83) MPa, respectively (P < 0.05). (5) The three-point flexural strength in the groups A, B, C and D was (961.07±75.53), (1 234.73±114.09), (1 024.28±120.51), and (1 036.09±80.10) MPa, respectively, among which the multiple comparison of groups A, C and D showed no significant difference (P > 0.05). (6) The effect of glaze technology on improving the flexural strength of yttria-stabilized tetragonal zirconia polycrystal ceramics is not as obvious as that of sandblasting, but the bond strength between tetragonal zirconia polycrystal ceramics and resin cements can be significantly improved with hydrofluoric acid etching and silanization after glaze.

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    Application of α-n-butyl 2-cyanoacrylate medical adhesive for repair of oral mucosal wound of rats
    Hu Kaiwei, Nie Ling, Zhang He, Li Yuzhou, Yang Sheng
    2020, 24 (16):  2526-2530.  doi: 10.3969/j.issn.2095-4344.2244
    Abstract ( 973 )   PDF (20116KB) ( 97 )   Save

    BACKGROUND: α-n-Butyl cyanoacrylate medical adhesive (504 medical adhesive) has good biocompatibility and anti-bacterial properties. It is a simple and effective medical adhesive. Little is reported on the application of α-n-butyl cyanoacrylate medical adhesive in surgical incision closure in the field of oral cavity.

    OBJECTIVE: To investigate the effect of α-n-butyl cyanoacrylate medical adhesive on oral mucosal wounds healing.

    METHODS: Fifteen female SD rat (Laboratory Animal Center of Chongqing Medical University, China) models of oral mucosal incisions were established and then divided into a natural healing group (without any treatment), silk suture group (interrupted stitches with absorbable surgical suture), and 504 medical adhesive group (wound closure with α-n-butyl cyanoacrylate medical adhesive) group. At 7 days after surgery, gross and histological observation was performed. Twenty female SD rats were established into models of 1 cm × 1 cm oral mucosa defect and then divided into two groups: a natural healing group (without any treatment) and a 504 closure group (covering the wound defect with α-n-butyl cyanoacrylate medical adhesive). At 10 days after surgery, gross and histological observation of defect area was performed. This study was approved by the Animal Ethics Committee of Chongqing Medical University, China.

    RESULTS AND CONCLUSION: Oral mucosal incision wound model: gross observation showed that the wounds in the three groups healed well, and no inflammatory reaction such as swelling and pus was found. Histological observation showed that the epithelium of the silk suture group was complete and continuous, the nail process of the epithelium was short and flat, the number of fibroblasts in the lamina propria increased, and a large number of inflammatory cells infiltrated in the suture track area. In the natural healing and 504 closure groups, the mucosal epithelium healed well, the nail process of the epithelium was thin and long, the fibroblasts in the lamina propria proliferated actively, and there were many collagen fibers. The fibers in the 504 closure group were arranged more closely and orderly than those in the silk suture group. Oral mucosa defect model: Gross observation showed that the wound in the natural healing group did not heal completely, and there was no infection such as swelling, necrosis, and ulceration. In the 504 closure group, wound surface basically healed. Histological observation revealed that in the natural healing group, mucosal defect was obvious, the epithelial layer was not closely connected with the lamina propria, necrotic tissue, a small amount of fibroblasts and a large number of inflammatory cells were observed. In the 504 closure group, the length of margin of mucosal defect was significantly reduced, fibroblast proliferation and vascular regeneration could be observed in the lamina propria, and fibers were orderly arranged. These results suggest that α-n-butyl cyanoacrylate medical adhesive has little foreign body reaction and can promote the regeneration of mucosal tissue, providing a potential method to close oral mucosal wound. 

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    Three-dimensional finite element analysis of different implant prostheses in maxillary anterior teeth region under different occlusal relationships
    Annikaer•Aniwaer, Palidaimu•Tuerti, Adili•Maimutimin, Zhang Fan, Niruti•Tuerxun
    2020, 24 (16):  2531-2536.  doi: 10.3969/j.issn.2095-4344.2259
    Abstract ( 353 )   PDF (30065KB) ( 41 )   Save

    BACKGROUND: In the treatment with dental implant prosthesis, the stress distribution of marginal bone and implant-bone interface is affected by the factors of restoration and occlusion. The internal structure and the stress distribution of implant-bone interface determine the long-term life of the implant and the stability of the marginal bone.

    OBJECTIVE: To analyze the effects of zirconia-based all-ceramic crown and Co-Cr alloy porcelain ceramic crown on the stress distribution of implant-bone interface, implant, prosthesis abutment, retention screw, and the inner structure in three occlusal relationships.

    METHODS: Using Mimics 17.0 software, the implant model of maxillary central incisor was established based on the cone beam CT of a patient undergoing prosthesis implantation into the maxillary central incisor. Two kinds of three-dimensional finite element models of zirconia-based all-ceramic crown and Co-Cr alloy porcelain ceramic crown were constructed. The edge to edge occlusion, normal occlusion and deep overbite were simulated to analyze the stress distribution of implant structure and the implant-bone interface in the three occlusal relationships.

    RESULTS AND CONCLUSION: (1) In the Co-Cr alloy porcelain ceramic crown group, when the occlusal relationship changed from the edge-to-edge occlusion to the normal occlusion and deep overbite relationships, the stress at the occlusal point of the prosthesis increased correspondingly, and the stress at the abutment, implant and the implant-bone interface decreased. In the normal occlusal relationship, the stress at the retention screw was more concentrated than that in the other two occlusal relationships, and its peak value of the equivalent stress was higher. (2) In the zirconia-based all-ceramic crown group, when the occlusal relationship changed from edge-to-edge occlusion to the normal and deep overbite relationships, the stress peaks of the abutment, implant and implant-bone interface decreased gradually. In the normal occlusal relationship, the stress peaks of the occlusal point and the retention screw were higher than those in the other two occlusal relationships. (3) In the edge-to-edge occlusion relationship, the peak of equivalent stress at the occlusal point of the implant prosthesis in the Co-Cr alloy porcelain ceramic crown group was slightly higher than that in the zirconia-based all-ceramic crown group. The peaks of equivalent stress of the abutment, retention screw, implant, and implant-bone interface in the Co-Cr alloy porcelain ceramic crown group were slightly lower than those in the zirconia-based all-ceramic crown group. In the normal occlusal relationship, the peak of equivalent stress at the neck of the implant in the Co-Cr alloy porcelain ceramic crown group was slightly higher than that in the zirconia-based all-ceramic crown group. In the deep overbite relationship, the peaks of the equivalent stress at the occlusal site of the implant prosthesis and the neck of the implant in the Co-Cr alloy porcelain ceramic crown group were higher than those in the zirconia-based all-ceramic crown group. The peaks of equivalent stress of the abutment, retention screw, and implant-bone interface in the Co-Cr alloy porcelain ceramic crown group were slightly lower than those in the zirconia-based all-ceramic crown group. (4) These results showed that different occlusal relationships and different upper structures of the implant prosthesis affected the stress distribution in each part of the implant and at the implant-bone interface. This finding may provide a reference for the prediction of long-term complications of implant prosthesis.

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    Effect of collagen scaffold on proliferation and osteogenic differentiation of human periodontal ligament stem cells treated by Eucommia ulmoides Oliver leaf extract
    Liu Yan, Chen Qingyu, Gao Xiang, Gao Junwu
    2020, 24 (16):  2537-2543.  doi: 10.3969/j.issn.2095-4344.2220
    Abstract ( 383 )   PDF (26777KB) ( 58 )   Save

    BACKGROUND: Collagen scaffold is a good tissue engineering material. However, there are no reports on the effects of collagen scaffold on the biocompatibility, proliferation, and osteogenic activity of human periodontal ligament stem cells (hPDLSCs) treated by Eucommia ulmoides Oliver leaf extract.

    OBJECTIVE: hPDLSCs treated by Eucommia ulmoides Oliver leaf extract were co-cultured with collagen scaffolds in vitro to investigate the morphological characteristics, adhesion, proliferation and osteogenic differentiation of hPDLSCs on collagen scaffolds.

    METHODS: In the experimental group, hPDLSCs treated by Eucommia ulmoides Oliver leaf extract were co-cultured with collagen scaffolds in vitro. In the positive control group, hPDLSCs were co-cultured with collagen scaffolds in vitro. In the blank control group, only hPDLSCs were cultured.

    RESULTS AND CONCLUSION: Scanning electron microscopy results revealed that in the experimental group, a large number of hPDLSCs adhered to the scaffold, and the synapses of the cells were closely connected with the scaffold. The cells grew well and contacted closely with each other. After co-culture for 4, 8 and 12 hours, cell adherence rate in both experimental and positive control groups increased and it in the experimental group was significantly higher than that in the positive control group (P < 0.05). MTT results showed that after 3, 5 and 7 days of co-culture, absorbance value in the experimental group was significantly higher than that in the positive control group (P < 0.05). After 7 and 14 days of osteogenic induction, alkaline phosphatase activity in the experimental group was significantly higher than that in the positive control group (P < 0.05). RT-PCR results showed that after 21 days of osteogenic stimulation, the expression of osteogenesis-related genes Runx2, OPN and OCN in the experimental group was significantly higher than that in the blank control group (P < 0.01), and the expression of the above genes in the experimental group was higher than that in the positive control group (P < 0.05). These data indicate that collagen scaffolds have good biocompatibility with hPDLSCs treated by Eucommia ulmoides Oliver leaf extract, can maintain cell morphology, and promote cell proliferation and osteogenic differentiation after co-culture.

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    Good cell compatibility and permeability of silk fibroin/chitosan composite scaffolds 
    Zhang Xiaoyun, Chen Yueping, Song Shilei, Zhang Chi, Zhuo Yinghong, Yang Nan, Zhan Huasong, Xu Canhong
    2020, 24 (16):  2544-2550.  doi: 10.3969/j.issn.2095-4344.2256
    Abstract ( 557 )   PDF (29178KB) ( 53 )   Save

    BACKGROUND: Silk fibroin and chitosan are commonly used as scaffolds in tissue engineering, but there are some shortcomings in their separate application. When they are mixed, they can be modified each other. They give full play to each other’s advantages and become ideal composite scaffolds.

    OBJECTIVE: To prepare Silk fibroin/chitosan composite scaffold and determineits properties.

    METHODS: The silk fibroin/chitosan composite scaffolds were prepared by freeze-drying method. The morphology and structure of the composite scaffolds were examined by scanning electron microscopy. The properties of the composite scaffolds were tested by thermogravimetric analysis, mechanical properties test, and cytotoxicity test. The quaternion chitosan was prepared. The nuclear magnetic resonance spectrum was detected by nuclear magnetic resonance instrument. The potential and particle size distribution were detected by Zeta potentiometer. The protection of DNA was detected by gel electrophoresis. The binding with DNA was observed by transmission electron microscope.

    RESULTS AND CONCLUSION: (1) The results of scanning electron microscopy showed that the silk fibroin/chitosan composite scaffolds had a good three-dimensional pore structure, with a pore size of 50-100 μm. (2) The results of thermogravimetric analysis showed that when the temperature was less than 200 °C, the mass loss rate of silk fibroin/chitosan composite scaffold was lower. When the temperature increased to 200-500 °C, the mass loss rate of the scaffold began to accelerate, and the loss amount increased. At 800 °C, the residual mass of the composite scaffold was 38%. (3) The maximum strain of silk fibroin/chitosan composite scaffold reached 94.94%, and the maximum stress was 7.01 MPa. (4) The results of CCK-8 experiment showed that silk fibroin/chitosan composite scaffolds had no cytotoxicity to rabbit bone marrow mesenchymal stem cells and had good cell compatibility. (5) The results of nuclear magnetic resonance spectra showed that the quaternion degree of quaternary ammonium chitosan was about 20%. (6) The particle size distribution of quaternized chitosan was (588.56±52.39) nm, and the surface of quaternized chitosan was positively charged with a potential of (16.3±3.92) mV, which was beneficial to the combination with DNA. (7) The results of gel electrophoresis experiments showed that the higher the proportion of quaternion chitosan, the better the encapsulation of DNA. When the ratio of chitosan/DNA was 1∶3, the encapsulation effect was achieved. (8) The results of transmission electron microscopy showed that most of the particles of quaternized chitosan/DNA were solid and round; the particle size difference was small; and the average particle size was about 200 nm. (9) The results showed that silk fibroin/chitosan composite scaffolds had a good biocompatibility and cell permeability, which was conducive to the growth of cells between scaffolds.

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    Skin flap transplantation combined with membrane induction technique for repair of long bone defects and soft tissue defects 
    Chen Yanming, Liu Mingjiang, Xie Songlin, Liu Changxiong, Song Jiangang
    2020, 24 (16):  2551-2555.  doi: 10.3969/j.issn.2095-4344.2260
    Abstract ( 280 )   PDF (22165KB) ( 124 )   Save

    BACKGROUND: Membrane induction technique for treating long bone defects has advantages of few complications, significant treatment efficacy and ease in operation. In previous studies, membrane induction technique was used to treat bone defect patients with good cartilage tissue, but there are few reports regarding bone defects with large area of cartilage tissue defect or accompanying infection.

    OBJECTIVE: To analyze the efficacy of flap transplantation combined with membrane induction technique for repairing long bone defects and soft tissue defects.

    METHODS: Fifteen patients with long bone defects and soft tissue defects who were treated in Affiliated Nanhua Hospital, University of South China from October 2016 to August 2018 were selected. They were aged (47.15±8.16) years. The soft tissue defect area was    5.1 cm × 3.4 cm-21.8 cm × 9.4 cm. The length of bone defect was 5.8-19.5 cm, with an average of (11.4±2.3) cm. The patients with mildly polluted wounds underwent debridement, external fixation of fracture, and filling bone cement in the bone defect area. Wounds were covered with local pedicle flaps or free flaps. Wound infection patients underwent vacuum sealing drainage, bone cement filling and flap surgery after infection was controlled. The second graft surgery was performed at 8 to 12 weeks after primary intention, and patients were followed up for 12 months. This study was approved by the Institutional Ethics Committee of Affiliated Nanhua Hospital, University of South China.

    RESULTS AND CONCLUSION: (1) Nine patients with mildly contaminated wounds were treated with external fixation after debridement, bone cement filling and flap transposition. No infection occurred. (2) Six patients with infection were treated with vacuum sealing drainage for 1 to 2 weeks. After the infection was controlled completely, bone cement filling and flap transplantation were conducted. All wounds were healed. (3) Fifteen patients achieved bone healing after second bone grafting. The healing time was between 8 and 12 months, with an average of (9.18±2.10) months. (4) These results suggest that skin flap transplantation combined with membrane induction technique can effectively treat patients with long bone defects and soft tissue defects.

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    Pathogenic distribution and drug resistance of bacterial biofilm on ureteral stent  
    Zhang Jiamo, Zhang Xuan, Luo Huaming, Zhao Tao, Chen Jiangchuan, Liu Juan, Wang Ke
    2020, 24 (16):  2556-2560.  doi: 10.3969/j.issn.2095-4344.2267
    Abstract ( 510 )   PDF (21663KB) ( 153 )   Save

    BACKGROUND: Ureteral stents have been extensively applied in the stenosis in the conjunction of the renal pelvis and ureter, the reconstruction of in situ urine flow, ureter or nephroscope lithotripsy, renal transplant, and tumors. However, the long-term retention of ureteral stents can induce catheter-associated urinary tract infection complications.

    OBJECTIVE: To investigate the morphological characteristics of bacterial biofilm on ureteral stent, and to analyze the features of pathogenic distribution and antimicrobial drug resistance to bacterial biofilm.

    METHODS: Specimens of ureteral stent were collected from 127 patients at Yongchuan Hospital, Chongqing Medical University between January and December 2016. The morphological characteristics of bacterial biofilm on the stent were observed under scanning electron microscope. Each specimen was divided into three parts (renal pelvis, ureter and bladder) for screening biofilm-forming bacteria strains separately by Congo red medium. The urine was bacterially cultured. Drug susceptibility test was done with the collected biofilm-forming bacteria strains. The study was approved by the Ethics Committee of Yongchuan Hospital, Chongqing Medical University (approval No. 201422).

    RESULTS AND CONCLUSION: (1) Bacterial biofilm was observed on the surface of ureteral stents at 7, 15 and 30 days of retention, with various numbers of inflammatory attachments or crystals. Bacteria on the bacterial biofilm were embraced by large amounts of fiber membranes. Patchy bacterial colonies were observed on the surface of the ureteral stent at 7 and 15 days of retention, which mainly focused on bacillus. Heap-shaped bacterial colonies were found on the surface of ureteral stents that were retained for 30 days, which mainly were bacillus and coccus. (2) A total of 106 bacterial biofilms were detected in the ureteral stent samples obtained from 127 patients. The positive rate was 83.5%, in which the bladder section had the highest positive rate, followed by the renal pelvis section and ureter section. There were 25 copies of positive urine culture, and the positive rate was 19.7%. The strains obtained from the bacterial biofilm on each section of the ureteral stents were significantly higher than that from the urine bacteria culture (P < 0.05). (3) A total of 227 strains were detected from 106 positive samples. Among these samples, the number of Gram-negative strains was significantly higher than that of Gram-positive strains (P < 0.05). Among culture bacteria of the bacterial biofilm on the ureteral stent and urine culture bacteria, colibacillus, pseudomonas aeruginosa, enterococcus faecalis and enterococcus faecium were the most common. (4) The biofilm-forming bacteria on the ureteral stent had a high drug resistance. (5) In summary, bacterial biofilm may be the important reason for catheter-associated urinary tract infection.

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    Changes in pain rating index, visual analogue score, and present pain intensity after far-infrared ceramic microsphere intervention for the treatment of muscle injury
    He Jianwei, Zhang Junmei, Zhang Ying, Xu Jian, Yang Xiaoling
    2020, 24 (16):  2561-2566.  doi: 10.3969/j.issn.2095-4344.2288
    Abstract ( 350 )   PDF (30832KB) ( 48 )   Save

    BACKGROUND: The far-infrared ceramic microspheres developed by the State Key Laboratory of "new ceramics and fine technology" of School of Materials, Tsinghua University, are made with ceramic colloidal injection molding technology. It is a new type of physical therapy material in the field of sports rehabilitation and daily health care. With its unique small circular structure, it can completely cover the damaged parts such as feet, waist, thigh, etc. to achieve comprehensive stimulation intervention.

    OBJECTIVE: To investigate the effect of far-infrared ceramic microspheres on pain intensity after muscle injury.

    METHODS: Thirty college students aged 18-21 years who met the diagnosis standard of posterior femoral muscle group injury were included in this study. All of them provided informed consent. They were randomly divided into three groups, with 10 students per group. Students in the massage group underwent massage therapy. Students in the far-infrared instrument group were treated with ordinary far-infrared therapeutic apparatus. Students in the far-infrared ceramic microsphere intervention group underwent far-infrared ceramic microsphere intervention. All treatments lasted 2 successive weeks. Before and 3, 7, and 14 days after treatment, McGill pain scale score (including pain rating index, visual analogue score and present pain intensity) was measured and compared within and between groups.

    RESULTS AND CONCLUSION: (1) Before treatment, there were no significant differences in pain rating index (sensory, affective, and total pain rating index scores), visual analogue score and present pain intensity between three groups (P > 0.05). (2) At 3 days of treatment, pain rating index, visual analogue score and present pain intensity score in the far-infrared ceramic microsphere intervention group were significantly lower compared with the massage and far-infrared instrument groups (P < 0.05). After 7 and 14 days of treatment, each studied indicator in the far-infrared ceramic microsphere intervention group was highly significantly lower compared with the other two groups (P < 0.01). (3) At 3 days of treatment, score of each pain indicator in the far-infrared ceramic microsphere intervention group was significantly lower compared with before treatment (P < 0.05), and it was significantly decreased compared with that measured concurrently in the other two groups (P < 0.05). (4) At 7 days of treatment, score of each pain indicator in the far-infrared ceramic microsphere intervention group was significantly lower compared with before treatment (P < 0.01), and it was significantly decreased compared with that measured concurrently in the other two groups (P < 0.05). (5) After 14 days of treatment, score of each pain indicator in the massage and far-infrared instrument groups was significantly lower compared with before treatment (P < 0.05). After 14 days of treatment, score of each pain indicator in the far-infrared ceramic microsphere intervention group was highly significantly lower compared with before treatment (P < 0.01). After 14 days of treatment, score of each pain indicator in the far-infrared ceramic microsphere intervention group was significantly lower compared with the other two groups. These findings suggest that far-infrared ceramic microsphere intervention can effectively reduce the degree of posterior femoral muscle group injury and effectively promote the recovery of muscle injury. 

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    Inflammatory reaction and lactic acid concentration after implantation of polylactic acid rib nail versus pure titanium embracing fixator in animals#br#
    Cheng Lei, Jin Jian, Hu Jingguo, Lu Yusong
    2020, 24 (16):  2567-2571.  doi: 10.3969/j.issn.2095-4344.2245
    Abstract ( 420 )   PDF (23261KB) ( 202 )   Save

    BACKGROUND: At present, the internal fixation materials for rib fractures in thoracic surgery include polylactic acid rib nails and pure titanium embracing devices. There are many clinical control studies on them, but there is no report on the molecular inflammatory response in vivo.

    OBJECTIVE: To investigate the inflammatory response of polylactic acid rib nails versus pure titanium embracing fixators in rabbits.

    METHODS: Sixteen New Zealand white rabbits (provided by Chengdu Dashuo Co., Ltd.) were divided into experimental group and control group. The right pectoralis major muscle of rabbits in the rib nail group was implanted with polylactic acid rib nails, and the right pectoralis major muscle of rabbits in the embracing fixator group was implanted with pure titanium embracing fixator. Femoral arterial blood was collected 3 days, 1 week, 2 weeks, 1 month, and 3 months after implantation. The concentrations of interleukin 1, interleukin-6, lactic acid and tumor necrosis factor alpha were detected by ELISA method. Three New Zealand white rabbits were taken, and the left pectoralis major muscle was implanted with poly-L-lactic acid rib nail, and the right pectoralis major muscle was implanted with pure titanium rib embracing device. At 1 week and 1 month, three grafted implants were implanted. Peripheral muscle tissue was observed for histopathology. This study was approved by the Medical Ethics Committee of Affiliated Hospital of Chengdu University.

    RESULTS AND CONCLUSION: (1) There were no significant differences in the concentrations of interleukin-1, interleukin-6, lactic acid and tumor necrosis factor-α between the two groups at 3 days, 1 week, 2 weeks, 1 month, and 3 months after implantation (P > 0.05). (2) At 1 week, the main pathological changes were necrosis of muscle fibers, infiltration of inflammatory cells and hyperplasia of fibrous tissue in the embracing fixator group, and necrosis of muscle fibers, infiltration of inflammatory cells and hyperplasia of fibrous tissue in the rib nail group. The necrosis degree of muscle fiber was less in the rib nail group than in the embracing fixator group. At 1 month, in the two groups, the number of inflammatory cells decreased, and the necrosis area was basically replaced by proliferated fibrous tissue. In the rib nail group, the muscle tissue morphology was relatively complete, and the area of tissue damage was small. At 3 months, the muscle morphology of the two groups was basically normal, and only a small amount of inflammatory cells infiltrated. (3) The results showed that the inflammatory response of polylactic acid rib nail and pure titanium embracing fixator in rabbits was comparable, without significant difference. Moreover, the concentration of lactic acid was not increased after the implantation of polylactic rib nail.

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    Application of environment-friendly bio-tissue sample preparation kit in fluorescence in situ hybridization detection of HER2 protein 2-positive invasive breast cancer 
    Qiu Xiaoyang, Wang Yuanyuan, Liu Chunpeng, Chen Hongcai, Wu Xuan, Zhan Xiaofen
    2020, 24 (16):  2572-2577.  doi: 10.3969/j.issn.2095-4344.1889
    Abstract ( 365 )   PDF (24769KB) ( 47 )   Save

    BACKGROUND: HER2 status assessment is an important biological index for the treatment and prognosis of invasive breast cancer. Pre-treatment of tissues such as immobilization, dehydration, transparency and dewaxing is a necessary procedure for HER2 protein and gene detection after pathological paraffin sections, and also an important factor affecting immunohistochemistry and fluorescence in situ hybridization.

    OBJECTIVE: To explore the application value of environment-friendly biological tissue sample preparation kit in fluorescence in situ hybridization detection of HER2 protein 2-positive invasive breast cancer.

    METHODS: 402 invasive breast cancer specimens were collected from Shantou Central Hospital from January 2015 to March 2019. The same specimens were semi-dissected and randomly divided into two groups. The control group was treated by traditional reagent formaldehyde immobilization-ethanol dehydration-xylene transparency and dewaxing, and paraffin sections were made. The experimental group was treated with formaldehyde immobilization-ethanol dehydration-xylene transparent dewaxing. Environment-friendly biological tissue sample preparation kit (including environmentally friendly stationary fluid, dehydration fluid, transparent liquid, dewaxing fluid) was used to make slices. The expression of HER2 protein was detected by immunohistochemistry. The amplification of HER2 gene was detected by fluorescence in situ hybridization in 131 invasive breast cancer specimens with positive HER2 protein expression.

    RESULTS AND CONCLUSION: The expression of HER2 protein in both experimental and control groups was specific and cell localization was correct. There were no significant differences in HER2 protein positive rate, uncertainty rate, and negative rate between the two groups (P > 0.05).The coincidence rate of HER2 protein expression between the two groups was 99.00%. The background of HER2 gene was clear in both groups, and the signals of HER2 and Ch17 double probes were clear. There was no cross-reaction and the double probe signal was precisely located in the nucleus of cancer cells. There was no significant difference in the number of successful cells between the two groups (P > 0.05). There was no significant difference in the positive rate and negative rate of HER2 gene amplification between the two groups (P > 0.05). The coincidence rate of HER2 gene amplification between the two groups was 97.71%. The average signal number of HER2 gene and the ratio of HER2/cells in both groups were all equal. There was no significant difference in the mean number of Ch17 signal, Ch17/cell ratio and HER2/Ch17 ratio between the two groups (P > 0.05). There was no significant difference in the total positive rate of HER2 between the two groups (P > 0.05). The results showed that compared with the traditional reagents, the invasive breast cancer samples prepared by environment-friendly bio-tissue sample preparation kit had no effect on HER2 protein expression. The expression of HER2 protein does not affect the amplification of HER2 gene, which can meet the needs of clinical detection.

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    In vitro corrosion and in vivo biosafety of pure magnesium film
    Sun Xirao, Wang Chengyue, Zhao Yuan, Zhang Zhenbao
    2020, 24 (16):  2578-2584.  doi: 10.3969/j.issn.2095-4344.2253
    Abstract ( 490 )   PDF (26715KB) ( 41 )   Save

    BACKGROUND: Magnesium and its alloys hold good mechanical properties, biocompatibility and degradability, which can be clinically used as the membrane guiding bone regeneration in guided bone regeneration technology.

    OBJECTIVVE: To explore the in vitro corrosion and in vivo biosafety of biodegradable high-purity magnesium film.

    METHODS: The pure magnesium sample and the pure titanium sample were respectively immersed in artificial saliva. After 7 and 14 days, the sample was taken out to observe the surface corrosion, the weight loss rate and the average corrosion rate of the sample, and the pH value in the artificial saliva were determined. Six healthy mongrel dogs (provided by the Experimental Animal Center of Jinzhou Medical University) were selected to establish a bilateral mandibular defect model. The left side was implanted with pure magnesium film and the right side was implanted with titanium film. At 12 weeks postoperatively, specimens of the mandibular experimental area were removed for gross observation and X-ray examination. The histopathological observation of major organs was performed at the same time. The study was approved by the Ethics Committee of Jinzhou Medical University.

    RESULTS AND CONCLUSION: (1) In vitro immersion test: pitting corrosion occurred on the surface of pure magnesium sample. Corrosion degradation became more and more serious with the immersion time. After 14 days of immersion, it showed surface corrosion. Pure titanium film showed no obvious corrosion. The pH value of the soaked pure magnesium film solution increased continuously, and it basically became balanced after 7 days, and remained at about 10. The pH value of pure titanium film was relatively stable, and slightly lower than that of pure magnesium film, and maintained at about 8.6. The weight loss rate of pure magnesium film immersed for 14 days was higher than that at 7 days (P < 0.05), and the average corrosion rate was lower than that of 7 days (P < 0.05). There was no obvious degradation behavior of pure titanium film, and no quality loss at each time point. (2) In vivo implantation experiment: film material in the pure magnesium film group was completely degraded, the trabecular bone arranged closely which formed a three-dimensional network structure, and some bone tissues were reconstructed into mature bones, but bone defects still existed. In the pure titanium film group, the defect area was filled with newly born bone tissue, the number of new trabecular bone was increased, and the trabecular bone in an order and tight arrangement. The bone volume fraction and bone pore volume fraction of the bone defect zone in the pure magnesium film group were significantly higher than those in the pure titanium film group (P < 0.05). There were no abnormalities in the liver and kidney structure of the experimental dogs, and no inflammatory cell infiltration was observed. (3) These results suggest that pure magnesium film can promote the bone healing in canine mandibular bone defect area, and the biosafety is good, but its corrosion resistance needs to be further improved.

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    Application of bioprinting in reconstruction of musculoskeletal interface
    Zhang Junwei, Cui Yutao, Li Zuhao, Wang Zhonghan, Liu He, Luo Wenbin
    2020, 24 (16):  2585-2591.  doi: 10.3969/j.issn.2095-4344.2270
    Abstract ( 386 )   PDF (40819KB) ( 51 )   Save

    BACKGROUND: Reconstruction of musculoskeletal interface is commonly involved in musculoskeletal injuries and degenerative diseases, while the key problem to achieve biological integration with the surrounding host tissues of musculoskeletal interface is fabricating substitution with precisely structural and material distribution. Bioprinting has made it possible to achieve artificial tissues with spatial controlled heterogeneity of physical properties and bioactive composition similar to native musculoskeletal interface tissues.

    OBJECTIVE: To introduce the structural and biofunctional properties of musculoskeletal interface tissues, as well as the application of bioprinting in the reconstruction of musculoskeletal interface.

    METHODS: The first author retrieved PubMed, Web of Science, Springerlink, Medline, WanFang and CNKI databases with “bioprinting, musculoskeletal interface” as English and Chinese search terms for relevant articles published from 2005 to 2019. Initially, 201 articles were retrieved, and finally 60 eligible articles were selected for further analysis.

    RESULTS AND CONCLUSION: Ideal bioprinted musculoskeletal interface grafts must be anisotropic as their native counterparts to sustain the changeful biomechanical environment in vivo. In addition, bioactivities of these implants must be preserved to initiate repair and replace the functions of defect area. The development of bioprinting approaches has brought promising prospect for the reconstruction of musculoskeletal interface, but there are still many challenges, such as the improvement of mechanical properties of bionic functional interface structure, the integration of multiple bionic structures, the vascularization of bioprinting structure, and the lack of in-depth research on the role of mechanical stimulation in the development and regeneration of interface tissue. For the future research direction of interface tissue engineering, it can be expected that seed cells, cytokines and gene therapy, as well as bioreactors will be included in the interface tissue engineering scaffolds, which will provide innovative solutions to solve the problem of interface tissue integration.

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    Repairing bone defects with heterogeneous calcined bone materials: characteristics, advantages and problems
    Li Fang, Wu Chao, Shi Qianhui, Cheng Yuting, Zhou Qian, Huo Hua, Qi Yuhan, Dong Qiang, Liao Jian
    2020, 24 (16):  2592-2598.  doi: 10.3969/j.issn.2095-4344.2269
    Abstract ( 429 )   PDF (794KB) ( 247 )   Save

    BACKGROUND: Insufficient alveolar bone volume in the dental implant area increases the difficulty of implant surgery, and the emergence of bone graft materials has successfully solved such problems. Among all single bone graft materials, xenogeneic calcined bone is widely used for the treatment of bone defects. However, there are still some disadvantages when using calcined bone alone.

    OBJECTIVE: To review the research progress in the repair of bone defects by heterogeneous calcined bone materials based on the latest relevant research trends.

    METHODS: The first author searched PubMed, VIP, WanFang and CNKI databases for relevant articles published from January 1986 to November 2019. The search terms were “calcined bone, xenogeneic bone, bone augmentation, bone substitute” in English and Chinese, respectively. Finally, 69 eligible articles were included for result analysis.

    RESULTS AND CONCLUSION: In all bone graft materials, calcined xenogeneic bone has good interconnectivity due to its similar characteristics to human bone structure. It facilitates the entry of vascular factors and osteogenic cells, provides channels and scaffolding for new bone formation, and has good biocompatibility and certain degradation, so it is preferred by surgeons. However, there are still some shortcomings, such as low solubility, slow absorption and poor mechanical property, which prompt researchers to develop a composite of calcined bone with ceramics, polymer, osteoinductive factor and metal ion. This can utilize the advantages of the involved materials, and thus the composite becomes a first choice of bone increment.

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    Hot issues of research on cells and biological scaffolds in cardiac tissue engineering
    Cai Zhibin, Wang Ping
    2020, 24 (16):  2599-2605.  doi: 10.3969/j.issn.2095-4344.2016
    Abstract ( 622 )   PDF (44446KB) ( 45 )   Save

    BACKGROUND: The emergence and development of cardiac tissue engineering provide a new choice for the treatment of cardiovascular diseases, especially for treating myocardial infarction.

    OBJECTIVE: To review the research progress of two core elements (cells and biological scaffolds) in cardiac tissue engineering, thereby providing reference and basis for the application of cardiac tissue engineering in the treatment of cardiovascular diseases.

    METHODS: Articles addressing cardiac tissue engineering in PubMed and CNKI databases published from 2010 to 2019 were searched. The search terms were “cardiac tissue engineering, cardiomyocytes differentiation, bone marrow derived stem cells, human embryonic stem cells, induced pluripotent stem cells, menstrual blood stem cells, biological scaffolds” in English and Chinese, respectively. Finally 78 eligible English articles were included.

    RESULTS AND CONCLUSION: Many kinds of cells (such as chondrocytes, skeletal muscle cells, cardiac fibroblasts, bone marrow derived stem cells, embryonic stem cells, induced pluripotent stem cells and menstrual blood-derived stem cells) and biological scaffolds (hydrogel, decellularized scaffold, cell sheet and cardiac chip) can be applied in cardiac tissue engineering. But there are still many problems to be solved in cardiac tissue engineering, such as suitable cell sources, development of novel scaffold materials, optimization of induced differentiation technology, optimization of implantation time and route.

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    Research and application of antibacterial modification of hydroxyapatite  
    Luo Jin, Yan Yajing, Tan Zhe, Zhang Han, Lan Hai
    2020, 24 (16):  2606-2613.  doi: 10.3969/j.issn.2095-4344.2264
    Abstract ( 420 )   PDF (48225KB) ( 45 )   Save

    BACKGROUND: Hydroxyapatite has been widely used in the studies on bone materials due to its good histocompatibility and bone conductivity. But pure hydroxyapatite has no antibacterial properties. Therefore, the antibacterial modification of hydroxyapatite is of great importance.

    OBJECTIVE: To review the research progress of the antibacterial modification of hydroxyapatite.

    METHODS: A computer-based retrieval of Science Direct online, PubMed, and CNKI databases was performed for the articles published before 2019. The key words were “antibacterial mechanism, hydroxyapatite, silver, gold, copper, cobalt, chitosan, strontium, zinc, gallium, magnesium, selenium, titanium” in English and Chinese, respectively. The irrelevant, repeated and old articles were excluded.

    RESULTS AND CONCLUSION: There are many ways to modify hydroxyapatite, but the main way is to add metal antibacterial particles. Silver, gold, copper, cobalt, chitosan, strontium, zinc, gallium, magnesium, selenium and titanium can be added into hydroxyapatite to make it have antibacterial activity. There are still some limitations in the research of antibacterial materials: the release curve of antibacterial ions in hydroxyapatite has not been well regulated. There are few antibacterial materials, let alone used for implants in vivo. More nontoxic substances with good antibacterial properties need to be found. Due to the toxicity of antibacterial ions, there is no uniform standard for the optimal concentration of each kind of antibacterial ion.

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    Network Meta-analysis of five common dressings in the treatment of pressure ulcer
    Huang Ruina, Huang Ruijia, Niu Caili, Wen Junmao, Liu Wanjun, Han Hui, Tian Ting, Wu Xiaowan
    2020, 24 (16):  2614-2619.  doi: 10.3969/j.issn.2095-4344.2293
    Abstract ( 598 )   PDF (26408KB) ( 95 )   Save

    BACKGROUND: There are many kinds of dressings for external use in treating pressure ulcer. Selecting a kind of dressing which is convenient, safe and effective can effectively increase the healing rate of pressure ulcer. 

    OBJECTIVE: To evaluate the effects of five common dressings on the treatment of pressure ulcer. 

    METHODS: A systematic search of Embase, PubMed, VIP, Elsevier, WanFang and CNKI were carried out with an end-point of July 2018. Randomized controlled trials about the therapeutic effects of different dressings on pressure ulcer were collected. All data were screened, extracted and assessed by two researchers independently. The ADDIS 1.16.8 software was adopted for data analysis. 

    RESULTS AND CONCLUSION: A total of 24 randomized control trials (1201 patients) which involved 5 kinds of dressings were included. The results of network Meta-analysis showed that the effect of hydrocolloid dressing and foam dressing were superior to aseptic gauze and vaseline gauze in treating pressure ulcer (P < 0.05). There was no difference in the therapeutic effect between the resting dressings (P > 0.05). Based on the probability ranking table, the therapeutic effects of five kinds of dressings in pressure ulcer were ranked as follows: hydrocolloid dressing > foam dressing > hydrogel dressing > sterile gauze > vaseline gauze. Hydrocolloid dressing and foam dressing were superior to the other dressings in the treatment of pressure ulcer.

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    Meta-analysis of dental implantation success rate in diabetic patients with 6% < glycated hemoglobin level < 8%
    Zhang Shuangyuan, Li Wenjin, Zhu Li, Wang Yu, Wei Zhoudan, Zhao Jiaoyang, Chen Yanan
    2020, 24 (16):  2620-2624.  doi: 10.3969/j.issn.2095-4344.2261
    Abstract ( 436 )   PDF (19948KB) ( 112 )   Save

    BACKGROUND: When glycated hemoglobin level is < 6%, the efficacy of dental implantation in diabetic patients is not significantly different from that in non-diabetic patients. However, there are few studies on whether the dental implantation success rate in diabetic patients with 6% < glycated hemoglobin level < 8% is decreased.

    OBJECTIVE: To evaluate the dental implantation success rate in diabetic patients with 6% < glycated hemoglobin level < 8%.

    METHODS: A computer-based retrieval of PubMed, Cochrane library, Embase, CNKI, and Wanfang databases was conducted for the articles published before December 2018. Retrospective and case-control studies comparing the dental implantation success rate between diabetic patients with 6% < glycated hemoglobin level < 8% and non-diabetic patients were retrieved. Data extraction and quality evaluation were performed by two researchers. Meta-analysis was carried out. OR and 95%CI values were used to estimate the success rate of dental implantation in diabetic patients with 6% < glycated hemoglobin level < 8%.

    RESULTS AND CONCLUSION: (1) Twelve studies were included, involving 2 698 patients and 9 414 implants. (2) Meta-analysis results showed that there was no significant difference in dental implantation success rate between non-diabetic patients and diabetic patients with 6% < glycated hemoglobin level < 8% [OR=1.13, 95%CI (0.82,1.54). (3) These results suggest that there is no significant difference in dental implantation success rate between diabetic patients with 6% < glycated hemoglobin level < 8% and non-diabetic patients.

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