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    08 February 2021, Volume 25 Issue 4 Previous Issue    Next Issue
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    Lumbar spinal tuberculosis implanted with artificial bone with streptomycin sulfate and percutaneous pedicle screw under transforaminal endoscopy
    Fu Shuanhu, Qin Kai, Lu Dahan, Qin Haibiao, Gu Jin, Chen Yongxi, Qin Haoran, Wei Jiading, Wu Liang, Song Quansheng
    2021, 25 (4):  493-498.  doi: 10.3969/j.issn.2095-4344.2358
    Abstract ( 271 )   PDF (769KB) ( 87 )   Save
    BACKGROUND: Animal model experiments on bone tuberculosis showed that calcium sulfate artificial bone loading could slowly and permanently release anti-tuberculosis drugs, increase local drug concentration, and repair local bone defects and promote bone fusion.
    OBJECTIVE: To evaluate the safety and efficacy of implantation of artificial bone with streptomycin sulfate and posterior percutaneous pedicle screw in the treatment of lumbar tuberculosis under transforaminal endoscopy after removal of lesions.
    METHODS: Twenty-eight patients with lumbar spinal tuberculosis who were treated in the First Affiliated Hospital of Guangxi University of Chinese Medicine from July 2016 to June 2019 were selected, including 10 males and 18 females, at the age of 36-69 years. Twelve patients in the experimental group received implantation of artificial bone with streptomycin sulfate and posterior percutaneous pedicle screw under transforaminal endoscopy after removal of lesions. Sixteen patients in the control group received bone graft fusion and internal fixation under anterior and posterior combined approach or bone graft fusion and internal fixation after posterior approach. Operation time, intraoperative blood loss, and hospital stay were recorded. At 3 months postoperatively and at the last follow-up, erythrocyte precipitation, C-reactive protein level and Cobb angle, visual analogue scale score, lumbar Japanese Orthopaedic Association score and Oswestry disability index score were compared between the two groups. The experiment was approved by the Ethics Committee of First Affiliated Hospital of Guangxi University of Chinese Medicine. 
    RESULTS AND CONCLUSION: (1) The operation time, intraoperative blood loss and hospital stay in the experimental group were all less than those in the control group (P < 0.05). (2) The erythrocyte sedimentation rate and C-reactive protein levels at 3 months after surgery and at the last follow-up in both groups were lower than those before surgery (P < 0.05), while those in the experimental group were lower than those in the control group (P < 0.05). (3) Visual analogue scale scores and Oswestry disability index scores of both groups were lower 3 months after surgery and at the last follow-up than those before surgery (P < 0.05), and lumbar  Japanese Orthopaedic Association score was higher than that before surgery (P < 0.05). The visual analogue scale score of the experimental group 3 months after operation was lower than that of the control group (P < 0.05). (4) Postoperative Cobb angle was lost in both groups, and there was no significant difference between the two groups (P > 0.05). (5) The results show that compared with the traditional posterior approach and combined anterior and posterior approaches in the treatment of lumbar tuberculosis, posterior lateral foramen endoscopic implantation of artificial bone with streptomycin sulfate combined with posterior percutaneous pedicle screw fixation can also achieve satisfactory clinical effect, and has the advantages of small trauma and rapid recovery. 
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    Comparison of different bioactive scaffolds in the treatment of regenerative pulp of young permanent teeth
    Li Wenjing, Li Haobo, Liu Congna, Cheng Dongmei, Chen Huizhen, Zhang Zhiyong
    2021, 25 (4):  499-503.  doi: 10.3969/j.issn.2095-4344.2359
    Abstract ( 294 )   PDF (691KB) ( 56 )   Save
    BACKGROUND: Regenerative endodontic therapy has the advantages of good biocompatibility, complete root development and high pulp vitality preservation rate. During vascular regeneration, scaffold is needed to maintain the survival of stem cells and vascular regeneration.   
    OBJECTIVE: To analyze the effect of different bioactive scaffolds on regenerative pulp of young permanent teeth.
    METHODS: Totally 160 patients (168 teeth) with acute pulpitis at the age of 8 to 16 years, who were treated in the Second Hospital of Hebei Medical University from June 2016 to June 2018, were enrolled in this study. The patients were divided into traumatic group (n=92) and dental caries group (n=76) according to a cause of a disease. Each group was subdivided into mineral trioxide aggregate (MTA), iRoot BP Plus, autologous platelet-rich fibrin (PRF)+MTA and acellular dermal matrix (ADM)+MTA subgroups. The corresponding stents were used to treat regenerative pulp. At 1, 3, 6, 12 and 24 months, the tooth color, pulp vitality, and eruption height were recorded. Root canal length, root canal wall thickness, periapical shadow and apical foramen closure were compared using X-ray photography; and the success rate was calculated. This study was approved by the Ethics Committee of Second Hospital of Hebei Medical University. 
    RESULTS AND CONCLUSION:  (1) At the final follow-up in the traumatic group, tooth color, pulp vitality and eruption height were not significantly different among the four scaffold subgroups (P > 0.05). Root canal length, root canal wall thickness, periapical shadow and apical foramen occlusion were significantly different among the four scaffold subgroups (P < 0.05). Among them, the effect was best in the PRF+MTA subgroup. (2) At the final follow-up in the dental caries group, tooth color, pulp vitality and eruption height were not significantly different among the four scaffold subgroups (P > 0.05). Root canal length, root canal wall thickness, periapical shadow and apical foramen occlusion were significantly different among the four scaffold subgroups (P < 0.05). Among them, the effect was best in the PRF+MTA subgroup. (3) No matter traumatic group or dental caries group, the success rate was significantly different among the four scaffold subgroups (P < 0.05); and the success rate was highest in the PRF+MTA subgroup. (4) Results verified that PRF combined with MTA has excellent biological induction in the treatment of young permanent teeth with regenerative pulp. Compared with other scaffolds, it can better preserve pulp vitality, induce the formation of young permanent teeth roots and improve the success rate of treatment.
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    Biphasic calcium phosphate loaded with advanced platelet rich fibrin can promote the activity of rabbit bone marrow mesenchymal stem cells
    Wang Yujiao, Liu Dan, Sun Song, Sun Yong
    2021, 25 (4):  504-509.  doi: 10.3969/j.issn.2095-4344.2360
    Abstract ( 264 )   PDF (1013KB) ( 21 )   Save
    BACKGROUND:  Adding growth factor to scaffold material can promote the proliferation and osteogenic differentiation of cultured stem cells in vitro and promote bone tissue regeneration. Advanced platelet rich fibrin (A-PRF) contains a variety of growth factors, which can promote the proliferation activity of a variety of cells and the expression of related functional proteins. 
    OBJECTIVE: To observe the effects of the sole and combined usage regarding A-PRF and biphasic calcium phosphate (BCP) on the growth of bone marrow mesenchymal stem cells. 
    METHODS: The third generation of rabbit bone marrow mesenchymal stem cells was cultured in four groups, including basic medium (blank group), A-PRF condition medium (A-PRF group), BCP (BCP group), A-PRF condition medium and BCP (A-PRF+BCP group). Cell proliferation activity was detected by CCK-8 assay. Cell adhesion was observed based on  methylrhodamine-phalloidin fluorescence staining. Intracellular alkaline phosphatase expression and mineralized nodules were quantitatively measured. 
    RESULTS AND CONCLUSION: (1) The absorbance value of proliferation of the A-PRF+BCP group was higher than that of the other three groups at 3, 5, 7, 11 and 14 days after culture. The absorbance value of proliferation of cells cultured in the A-PRF group was higher than that of the BCP group and the blank group at 1, 3 and 5 days after culture. The absorbance value of proliferation of BCP group was higher than that of the A-PRF group and the blank group at 7, 11 and 14 days after culture. (2) Methylrhodamine-phalloidin fluorescence staining showed that bone marrow mesenchymal stem cells in the BCP group and the A-PRF+BCP group adhered to the surface of BCP and the number of cells and microfilaments in the A-PRF+BCP group was higher than that in BCP group. (3) The synthesis of mineralized nodules was A-PRF+BCP group > BCP group > A-PRF group > blank group at 1, 21 and 28 days after surgery. (4) The expression of alkaline phosphatase was A-PRF+BCP group > BCP group > A-PRF group > blank group at 5, 7 and 9 days. There was significant difference between the two groups (P < 0.05). (5) The results showed that BCP exerted a weak influence on promoting cell proliferation in the early stage, but its effect of scaffold was apparent. A-PRF had a significant effect on promoting cell proliferation with considerable influence on promoting cell proliferation and differentiation when combined BCP.
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    Decalcified bone matrix and lentivirus-mediated silencing of P75 neurotrophin receptor transfected bone marrow mesenchymal stem cells to construct tissue-engineered bone
    Chen Junyi, Wang Ning, Peng Chengfei, Zhu Lunjing, Duan Jiangtao, Wang Ye, Bei Chaoyong
    2021, 25 (4):  510-515.  doi: 10.3969/j.issn.2095-4344.2361
    Abstract ( 200 )   PDF (784KB) ( 22 )   Save
    BACKGROUND: P75 neurotrophin receptor (P75NTR) has a bidirectional role in promoting and inhibiting bone formation in bone tissue. Overexpression of P75NTR can inhibit the osteogenic mineralization of bone marrow mesenchymal stem cells. P75NTR can inhibit the degradation of fibrin and the formation of new blood vessels around the fracture, leading to fracture nonunion. Its inhibition of bone tissue repair is related to its mediating apoptosis channels. 
    OBJECTIVE: To study the effect of silencing P75NTR on the growth activity and alkaline phosphatase activity of bone marrow mesenchymal stem cells, and to study the ectopic osteogenesis ability implanted in demineralized bone matrix to construct tissue engineering bone complex.
    METHODS: Lentivirus-mediated silencing P75NTR was transfected into bone marrow mesenchymal stem cells. The expression of fluorescent protein and P75NTR protein was detected by fluorescence inverted phase contrast microscope and western blot assay. Two or three days after transfection, CCK-8 assay was used to detect cell activity. After osteogenic induction solution induced differentiation culture for 7 and 14 days, alkaline phosphatase activity was detected by enzyme labeling method. Lentivirus-mediated silencing P75NTR transfected bone marrow mesenchymal stem cells were cultured with compound demineralized bone matrix. Optical inverted phase contrast microscope and scanning electron microscope were used to observe the adhesion of demineralized bone matrix and bone marrow mesenchymal stem cells. After further osteogenic differentiation for 7 days, tissue engineered bone complex was subcutaneously implanted in the rat back for 4 weeks. The osteogenesis was observed by hematoxylin-eosin staining and alkaline phosphatase staining.   
    RESULTS AND CONCLUSION: (1) Lentiviral-mediated silencing P75NTR transfection rate was approximately 70%. The expression of P75NTR target protein was significantly lower than that of untransfected group and negative virus control group (P < 0.05). (2) Compared with untransfected group and negative virus control group, the cell activity of silencing P75NTR transfected group increased significantly at 5 and 6 days (P < 0.05). Compared with the untransfected group and the negative virus control group, the alkaline phosphatase activity of silencing P75NTR transfected group increased significantly at 7 and 14 days after osteogenic induction (P < 0.05). (3) Silencing P75NTR transfected bone marrow mesenchymal stem cells and demineralized bone matrix formed a good adhesion; the tissue engineered bone complex significantly enhanced the ability of ectopic bone formation. (4) The results showed that bone marrow mesenchymal stem cells transfected with silencing P75NTR mediated by lentivirus could be implanted in decalcified bone matrix to form a good tissue engineered bone complex, which has a certain heterotopic osteogenesis effect and provides important theoretical basis for bone tissue engineering in the treatment of bone defects. 
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    Measurement and statistical analysis of trabecular morphological parameters of titanium alloy peri-prosthesis under preload
    Li Chenjie, Lü Linwei, Song Yang, Liu Jingna, Zhang Chunqiu
    2021, 25 (4):  516-520.  doi: 10.3969/j.issn.2095-4344.2849
    Abstract ( 204 )   PDF (743KB) ( 28 )   Save
    BACKGROUND: The implantation of titanium alloy prosthesis would produce stress shielding to damage mechanical microenvironment of bone tissue. This might affect normal bone remodeling process. Interference fit was used to generate preload to reconstruct mechanical microenvironment in this area. It may have important theoretical significance and clinical application value to promote bone remodeling in the mid-long-term after surgery.
    OBJECTIVE: To analyze the promoting effect of preload on osseointegration of porous titanium alloy prosthesis.
    METHODS: Fourteen male New Zealand rabbits were divided into two groups. The three-dimensional (3D) printed titanium alloy prosthesis was implanted into the outside of right femoral condyle with interference fit in experimental group (n=7). Rabbits in the control group (n=7) were feed free. Femurs at the surgery side were extracted at 12 weeks after surgery. Micro-CT scanning and 3D reconstruction were performed to measure bone density and trabecular morphological parameters around the prosthesis. Animal experiment was approved by Animal Ethics Committee of Tianjin Institute of Medical Science (approval No. IMPS-EAEP-Z-2019108-01). 
    RESULTS AND CONCLUSION: (1) Bone mineral density was reduced significantly in the experimental group compared with the control group (P < 0.05). (2) Bone volume fraction, trabecular thickness, trabecular number were reduced in the experimental group compared with the control group (P < 0.05). Bone surface area ratio and trabecular separation were larger in the experimental group than those in the control group (P < 0.05). There was no significant change in degree of anisotropy between the two groups (P > 0.05). (3) The results showed that preload could promote osseointegration of porous titanium alloy prosthesis. However, the structural characteristics of the in-growth bone were worse than healthy bone. This might lead to a high fracture risk in the mid-long-term after surgery.
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    Metal-ceramic interface characteristics of Co-Cr alloy fabricated by selective laser melting
    Sun Qi, Zhou Yanan, Dong Xin, Li Ning, Yan Jiazhen, Shi Haojiang, Xu Sheng, Zhang Biao
    2021, 25 (4):  521-525.  doi: 10.3969/j.issn.2095-4344.2362
    Abstract ( 211 )   PDF (1067KB) ( 49 )   Save
    BACKGROUND: Co-Cr ceramic alloys made by selective laser melting technology are widely used in the field of dental restoration, but the influence of selective laser melting technology on the bonding properties of Co-Cr ceramic alloys is still controversial. 
    OBJECTIVE: To explore the metal-ceramic interface characteristics of dental Co-Cr alloy fabricated by selective laser melting. 
    METHODS:  Metal-ceramic specimens were prepared by selective laser melting and precision casting, respectively. Metal-ceramic bond strengths, interface characteristics, fracture analysis, microstructures and composition distribution of specimens were obtained with the aid of universal testing machine, metallographic microscope, scanning electron microscope coupled with energy disperse spectrometer.  
    RESULTS AND CONCLUSION: (1) The metal-ceramic bond strengths of precision casting Co-Cr alloy was higher than that of selective laser melting Co-Cr alloy       (P < 0.05). (2) Metallographic microscope showed that selective laser melting Co-Cr alloy had fine grains and a more uniform matrix. Precision casting Co-Cr alloy showed typical casting dendritic structure with coarse grains and a large number of island second phase structures. (3) Scanning electron microscopy showed that precision casting Co-Cr alloy had a thicker diffusion layer than the selective laser melting Co-Cr alloy at the metal-ceramic interface. (4) Scanning electron microscopy showed that the metal-ceramic specimens of precision casting Co-Cr alloy tended to cohesive fracture, and the metal-ceramic specimens of selective laser melting Co-Cr alloy tended to adhesive fracture. (5) The results showed that although the bonding strength of selective laser melting Co-Cr alloy was lower than that of precision casting Co-Cr alloy, the bonding strength of selective laser melting Co-Cr alloy could still meet the requirements of standard YY0621.1-2016.
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    Anti-hepatoma activity of targeted Pluronic F127/formononetin nanocomposite system in vitro
    Liu Yang, Gong Yi, Fan Wei
    2021, 25 (4):  526-531.  doi: 10.3969/j.issn.2095-4344.2364
    Abstract ( 246 )   PDF (1093KB) ( 37 )   Save
    BACKGROUND: Natural flavonoid formononetin (FN) is traditional Chinese medicine extract and has anticancer effect, but the hydrophobic structure and short half-life in vivo limit their clinical applications.  
    OBJECTIVE: To prepare FN loaded pluronic (PF)-folic acid (FA) conjugated micelles (FN-PF-FA) and to test in vitro drug release and anticancer activity.
    METHODS: FA coupling PF was prepared by carbodiimide crosslinker chemical method. FN-PF-FA micelles were prepared by film hydration method. The encapsulation efficiency, drug loading and drug release performance of FN-PF and FN-PF-FA micelles were measured. The in vitro anti-cancer activity of flavin, FN-PF micelles, and FN-PF-FA micelles on folic acid-overexpressing human liver cancer HepG2 cells was measured by in vitro thiohodamine B experiment. 
    RESULTS AND CONCLUSION: (1) The encapsulation efficiency of FN-PF and FN-PF-FA micelles was (84.12±2.15)% and (82.50±1.78)%, respectively, and the drug loading was (21.33±2.27)% and (19.73±1.58)%, respectively. (2) The release rate of both micelles in acidic environment was faster than that in alkaline environment. In the same condition, the release rate of FN-PF-FA micelles was slower than that of FN-PF micelles. (3) At the same drug concentration, the ability of FN-PF micelles and FN-PF-FA micelles to inhibit the proliferation of human liver cancer HepG2 cells was stronger than that of free FN (P < 0.05). Moreover, the inhibitory effect of FN-PF-FA micelles was stronger than that of FN-PF micelles (P < 0.05). (4) The order of drug concentration required to inhibit tumors was FN-PF-FA < FN-PF < free FN, and there was a significant difference between groups (P < 0.01). (5) Results suggested that FN-PF-FA micelles had the potential to target the release of anticancer drugs.
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    Influence of novel nanoscaffolds on biological behaviors of neural stem cells and the related gene expression
    Zhou Jihui, Yao Meng, Wang Yansong, Li Xinzhi, Zhou You, Huang Wei, Chen Wenyao
    2021, 25 (4):  532-536.  doi: 10.3969/j.issn.2095-4344.2363
    Abstract ( 231 )   PDF (738KB) ( 25 )   Save
    BACKGROUND: The scaffold made by nanotechnology may have a similar surface structure to basement membrane of natural organism, which can effectively regulate the behavior of seed cells.   
    OBJECTIVE: To observe the effects of parallel and staggered nanofiber membranes on the proliferation and differentiation of neural stem cells. 
    METHODS: The parallel and staggered nanofiber membranes were prepared using electrostatic spinning technology with type I collagen as raw material. Neural stem cells of newborn rats were seeded on the surface of two kinds of nanofiber membranes. Cell culture alone was used as control. Cell proliferation was detected by MTT assay. Cell proliferation cycle was detected by flow cytometry. Cell differentiation rate was detected by immunohistochemistry. The gene expression of Bcyclin D1 aned CDK2 was detected by real-time quantitative polymerase chain reaction.  
    RESULTS AND CONCLUSION: (1) The absorbance values of cell proliferation of parallel arrangement group and staggered arrangement group at 1, 3, 5, 7 and 9 days were higher than that of the control group (P < 0.05). The absorbance value of cell proliferation of parallel arrangement group was higher than that of staggered arrangement group at 3, 5, 7 and 9 days (P < 0.05). (2) Cell differentiation rate in the parallel arrangement group and the staggered arrangement group was higher than that in the control group (P < 0.05), and that in the parallel arrangement group was higher than that in the staggered arrangement group (P < 0.05). (3) Immunohistochemistry showed that there was no significant difference in neuronal differentiation rate among the three groups (P > 0.05). (4) Real-time quantitative polymerase chain reaction demonstrated that the expression of Bcyclin D1 and CDK2 was higher in the parallel arrangement group and staggered arrangement group was higher than in the control group (P < 0.05); and the expression was higher in the parallel arrangement group than in the staggered arrangement group (P < 0.05). (5) The results confirmed that parallel and staggered nano tissue engineering can promote the proliferation of neural stem cells, but has no significant effect on cell differentiation, and can regulate the biological behavior of neural stem cells from the level of gene expression.
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    Stress of three-dimensional finite element models of E-MAX porcelain inlay
    Zhang Guomei, Zhu Jun, Hu Yang, Jiao Hongwei
    2021, 25 (4):  537-541.  doi: 10.3969/j.issn.2095-4344.2365
    Abstract ( 260 )   PDF (1012KB) ( 30 )   Save
    BACKGROUND: E-Max porcelain inlay has good aesthetic, bonding and mechanical properties, and has a broad application prospect in the field of tooth defect repair. 
    OBJECTIVE: To build the model of mesio-occluso-distal cavity E-Max porcelain inlay with different adhesives and different depths of holes, and to explore the stress distribution and regional law of different data models.
    METHODS: Micro-CT was used to scan the human mandibular third molar model. Medical modeling software mimics 20, reverse engineering software Geomagic Studio 2014, and three-dimensional mechanical drawing software NX 10 were utilized to construct the three-dimensional finite element models of mesio-occluso-distal cavity E-Max porcelain inlay with different adhesives and different depths of holes: Group A with a hole depth of 2 mm, using 3M RelyX™ Unicem adhesive; group B with a hole depth of 3 mm, using 3M RelyX™ Unicem adhesive; group C with a hole depth of 4 mm, using 3M RelyX™ Unicem adhesive; group D with a hole depth of 2 mm, using vario-link N adhesive; group E with a hole depth of 3 mm, using vario-link N adhesive; group F with a hole depth of 4 mm, using vario-link N adhesive. Finite element analysis software ANSYS workbench 18.2 was used for meshing. Stress distribution of each model at 10 N•mm torque, 45° loading 175 N and 90° loading 600 N was analyzed.  
    RESULTS AND CONCLUSION: (1) After 10 N•mm torque loading, with the increase of cavity depth, total displacement of the teeth and the equivalent stress of the periodontal ligament decreased with the same adhesive; when the cavity depth was 3 mm, the root surface equivalent stress and the adhesive equivalent stress were largest. Under the same cavity depth, the equivalent stress and the maximum principal stress of the root surface were larger when using vario link N adhesive. (2) When 175 N was applied at 45° lingual direction and the same adhesive was used, the equivalent stress on the root surface decreased with the increase of the cavity depth. When the depth of the cavity was 4 mm, the total displacement of the tooth and the equivalent stress of the adhesive were largest. When the cavity depth was 2 mm, the equivalent stress and the maximum principal stress of periodontal ligament were largest. At the same cavity depth, the maximum principal stress, equivalent stress of root surface and equivalent stress of periodontal membrane of models using 3M RelyX™ T Unicem adhesive were higher and equivalent stress of the adhesive smaller than those of other models. (3) When 600 N was applied at 90° lingual direction and the same adhesive was used, with the increase of the cavity depth, the total displacement of the tooth and the equivalent stress of the periodontal membrane decreased. When the cavity depth was 3 mm, the maximum principal stress of the root surface and the equivalent stress of the adhesive were maximum; when the cavity depth was 4 mm, the maximum principal stress of periodontal ligament was largest. At the same cavity depth, the equivalent stress of the root surface, the total displacement of the tooth, the maximum principal stress and the maximum principal stress of the root surface were high, while the equivalent stress of the adhesive was small in models using 3M RelyX™ Unicem adhesive. (4) Results indicate that stress concentration areas are the root bifurcation area, the inlay edge line, the pulp chamber top, and the gingival wall; and key areas of stress concentration and destruction are the bonding interface, the gingival wall and the root bifurcation area in the three-dimensional finite element models of mesio-occluso-distal cavity E-Max porcelain inlay.
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    Nano-hydroxyapatite/polyamide 66 composite filling combined with locking plate in the treatment of fibrous dysplasia of femoral bone
    Liu Jiangfeng
    2021, 25 (4):  542-547.  doi: 10.3969/j.issn.2095-4344.2366
    Abstract ( 225 )   PDF (824KB) ( 33 )   Save
    BACKGROUND: Nano-hydroxyapatite/polyamide 66 composite (n-HA/PA66) has good biocompatibility, osteoinduction, osteoconductivity and osteogenesis. It is widely used in clinical fracture healing, spinal fusion, and other bone repair. 
    OBJECTIVE: To observe the effect of n-HA/PA66 filling combined with locking plate in the treatment of fibrous dysplasia of femoral bone.
    METHODS: From May 2015 to May 2018, 15 patients with fibrous dysplasia of bone were admitted to Xingtai People’s Hospital Affiliated to Hebei Medical University. There were 4 males and 11 females, aged 16-58 years. The lesions were all located in the femur. They were all treated with n-HA/PA66 filling combined with locking plate. The patients were followed up for 18-40 months. Imaging examination (X-ray and CT scan) was carried out to evaluate the bone healing. Musculoskeletal Tumor Society (MSTS) score and Harris score were used to assess the functional recovery of patients after operation.  
    RESULTS AND CONCLUSION: (1) X-ray films showed that there was a clear boundary between the transplanted bone and the host bone immediately after the operation. At 3 months after the operation, the transplanted bone was replaced partly by crawling. At 6 months, new bone formation was obvious. At 9-12 months, new bone formed completely. The transplanted bone was basically catabolized. At 18 months, the new bone was completely integrated with the host bone. The boundary between the new bone and the host bone disappeared. New bone and host bone are connected by direct trabecula. (2) At the last follow-up, CT images showed that the local lesions were eliminated; no recurrence or metastasis occurred; and the grafts healed completely. The G/N ratio was 0.78±0.09. (3) At the last follow-up, 15 patients’ pain all disappeared, MSTS score was 28.1±0.7. Harris score was 94.3. Daily physical activity was restored. (4) n-HA/PA66 composite material has obvious osteogenic effect on the bone defect caused by the removal of fibrous dysplasia. Locking plate fixation can make patients move early and obtain good postoperative function.
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    Changes of abdominal wall mechanics and pain after tension-free inguinal hernia repair with polypropylene mesh
    Li Quanxi, Shen Yu, Wan Wei, Sun Shanzhi
    2021, 25 (4):  548-552.  doi: 10.3969/j.issn.2095-4344.2367
    Abstract ( 219 )   PDF (712KB) ( 66 )   Save
    BACKGROUND: Chronic pain after tension-free inguinal hernia repair is a common postoperative complication. An important cause of chronic pain is nerve injury. 
    OBJECTIVE: To observe the effect of iliohypogastric nerve preposition on chronic pain after inguinal hernia repair and analyze its mechanics. 
    METHODS: Totally 76 male inguinal hernia patients, from August 2013 to November 2016, aged 36-95 years in Second People’s Hospital of Lianyungang were selected. The patients were all treated with large-size polypropylene non-absorbable mesh insertion. The iliohypogastric nerve was placed in front of the mesh. Pain was followed up at 3, 6, and 12 months after operation. This study was approved by the Ethics Committee of Second People’s Hospital of Lianyungang.  
    RESULTS AND CONCLUSION: (1) No chronic pain or recurrence was found in the 76 patients at 3, 6 and 12 months after surgery. (2) The pressure included vertical pressure and tangent pressure formed from intra-abdominal pressure on abdominal wall, directly affecting abdominal wall and artificial repair materials. This was the basic cause of the relative mechanical relationship between nerve and mesh. (3) The results showed that the tension-free inguinal hernia repair with the iliohypogastric nerve preposition could reduce the incidence of postoperative chronic pain, which may be related to the effect of postoperative abdominal pressure on tissue repair, especially the repair around the mesh. 
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    Preparation and properties of copper-loaded antibacterial functional film on titanium surface
    Li Xingping, Xiao Dongqin, Zhao Qiao, Chen Shuo, Bai Yiguang, Liu Kang, Feng Gang, Duan Ke
    2021, 25 (4):  553-557.  doi: 10.3969/j.issn.2095-4344.2368
    Abstract ( 252 )   PDF (1353KB) ( 46 )   Save
    BACKGROUND: Titanium implants are widely used in the field of contemporary orthopedics due to their good histocompatibility and biological inertia. However, titanium implants alone are difficult to meet complex clinical needs, such as bacterial infections and slow bone regeneration, so it is urgent to develop titanium implants with biological functions.
    OBJECTIVE: To evaluate its antibacterial function and cellular activity in vitro, the cupride-carrying functional membrane was prepared on the surface of titanium in view of the important role played by copper ions in antibacterial activities.
    METHODS: Poly(lactic acid) films containing different concentrations of copper ions (0, 0.1, 0.5, 1.0 g/L, and  assigned to groups B, C, D, and E) were prepared on the surface of the titanium sheet by dipping. Staphylococcus aureus and escherichia coli were co-cultured with pure titanium tablets (group A) and four kinds of poly(lactic acid) coated titanium tablets. The formation and adhesion of bacterial colonies were observed by scanning electron microscopy. Living/dead bacteria were stained to observe the bacterial state. Bone marrow mesenchymal stem cells were cultured with five groups of titanium tablets (or five kinds of titanium samples after immersion in DMEM for 6 hours). Cell proliferation was evaluated by CCK-8 method. 
    RESULTS AND CONCLUSION: (1) General observation showed that the number of bacterial colonies in the petri dish was largest and they were evenly distributed in groups A and B. The number of bacterial colonies close to the titanium sheet area decreased, while the number of bacterial colonies far away from the titanium sheet area was large in groups C and D. No obvious colony formation was found in group E. Scanning electron microscopy showed that a large number of bacteria adhered to the surface of groups A and B, while the number of bacteria adhered to the surface of groups C, D and E gradually decreased. (2) Living/dead bacteria staining showed that the bacterial survival rate in groups A and B was above 95%, and that in groups C, D and E was below 5%. The bacterial survival rate decreased with the increase of copper ion concentration in the membrane. (3) CCK-8 detection of cells in contact culture with titanium tablets showed that compared with group A, the proliferation of bone marrow mesenchymal stem cells in group C was obvious, and the proliferation of cells in groups D and E was inhibited. CCK-8 detection of cells cultured with titanium slices showed that compared with group A, the proliferation of cells in groups C, D and E was significant. (4) The results showed that when the copper ion content in poly(lactic acid) solution was 0.1 g/L, the poly(lactic acid) film prepared on the surface of titanium had the strongest cell proliferation promoting capacity, but the bactericidal capacity was relatively weak. When the ion content was 1.0 g/L, the bactericidal capacity was the strongest. DMEM immersion for 6 hours showed no cytotoxicity. Therefore, the preparation of copper-loaded poly(lactic acid) film with appropriate concentration on the surface of titanium sheet can endow the antibacterial properties of the implant surface.
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    Influencing factors and biological property of novel biomedical materials: porous silicon carbide coated with bioactive tantalum
    Ma Zhijie, Li Jingyu, Cao Fang, Liu Rong, Zhao Dewei
    2021, 25 (4):  558-563.  doi: 10.3969/j.issn.2095-4344.2369
    Abstract ( 262 )   PDF (1580KB) ( 71 )   Save
    BACKGROUND: Porous silicon carbide has excellent physical and chemical properties and can be used to repair complex shapes and long weight-bearing bone defects, but it has no biological activity and cannot promote bone remodeling and integration.
    OBJECTIVE: A tantalum (Ta) coating was deposited on the surface of the porous silicon carbide scaffold to evaluate its biological activity.
    METHODS: The chemical vapor deposition method was used to deposit a Ta coating on the surface of the porous silicon carbide scaffold. The optimal experimental parameters were explored by setting different gas reaction flow rates and temperatures. The Ta coating was prepared with the best experimental parameters to test the mechanical properties of porous Ta. Human osteoblasts were co-cultured with the Ta coating specimens, and were observed by scanning electron microscopy after 3 and 7 days of cultivation.
    RESULTS AND CONCLUSION: (1) After the optimization of experimental parameters, the best experimental conditions were controlled as follows: deposition temperature of 1 050 °C, hydrogen flow rate of 180 mL/min and chlorine flow rate of 100 mL/min. (2) The compressive strength of the Ta coated specimen was (61.4±3.2) MPa; the yield strength was (45.8±2.9) MPa; and the elastic modulus was 4.8 GPa. (3) Scanning electron microscopy demonstrated that after 3 days of co-cultivation, a large number of cells adhered to the surface of the porous silicon carbide scaffold that is coated with Ta and the porous structure. Some of the cells protruded from the pseudopod and were connected to each other. After 7 days of co-cultivation, the cell protrusions fused to form a sheet covering the surface of the porous Ta. In the porous structure, the cells protruded from the pseudopods, cross-linked to each other across the pores, secreted in the matrix, and coated the microparticle structure, gradually spreading in the pores. (4) The results show that the Ta coating on the surface of porous silicon carbide scaffold has good mechanical properties and biological activity.
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    Three-dimensional printing technology and bone tissue engineering research: literature metrology and visual analysis of research hotspots
    Wu Zijian, Hu Zhaoduan, Xie Youqiong, Wang Feng, Li Jia, Li Bocun, Cai Guowei, Peng Rui
    2021, 25 (4):  564-569.  doi: 10.3969/j.issn.2095-4344.2370
    Abstract ( 308 )   PDF (847KB) ( 39 )   Save
    BACKGROUND: With the continuous development of three-dimensional (3D) printing technology and bone tissue engineering, more and more studies have applied 3D printing technology to bone tissue engineering, but the main research status, hot spots and development trend are not clear enough.
    OBJECTIVE: To explore the current research status, hotspots and development trends of this field through the literature metrology and visual analysis of research hotspots of 3D printing and bone tissue engineering.
    METHODS: The CNKI database was searched under the theme of “3D printing and bone tissue engineering research”. Based on the quantitative visual analysis method of CNKI literature, the author made a statistical analysis on the trend of the number of publications, publishing institutions and journals of the application of 3D printing technology in bone tissue engineering. VOSviewer software was used to analyze the author collaboration and keyword co-occurrence network of the literature, and the hot research topic was interpreted based on the literature.
    RESULTS AND CONCLUSION: (1) A total of 469 effective articles related to 3D printing and bone tissue engineering were retrieved. Since 2014, the research on 3D printing and bone tissue engineering has shown a steady growth trend. Chinese Journal of Tissue Engineering Research and Jilin University are the most published journal and institution in this field, respectively. The authors of the literature form five major groups, but there is very little cooperation between the groups. (2) Keywords co-occurrence network shows that the contents revealed by keywords commonly clustering into four research topics (bone tissue engineering scaffold material, 3D printing technology and its application in orthopedics, 3D printing and joint replacement, and others) and the top 10 keywords (3D printing technology, computer aided technology, bone tissue engineering, tissue engineering, fracture, bone defect, hydroxyapatite, three-dimensional, replacement, titanium alloy) really reflect the present situation and the hotspots of current 3D printing and the bone tissue engineering research, which can provide a reference for researchers in this field when choosing a research direction. 
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    Effect of thrombin concentration on the prevention of postoperative cerebrospinal leakage by fibrin glue
    Cheng Jun, Tan Jun, Zhao Yun, Cheng Fangdong, Shi Guojia
    2021, 25 (4):  570-575.  doi: 10.3969/j.issn.2095-4344.2371
    Abstract ( 294 )   PDF (762KB) ( 38 )   Save
    BACKGROUND: Fibrin glue is commonly used to prevent postoperative cerebrospinal fluid leakage from dural injuries. However, fibrin glue with standard-concentration thrombin coagulates too fast, resulting in poor adhesion of dural mater. Effect of low-concentration thrombin fibrin glue on sealing dural injuries to prevent cerebrospinal fluid leakage is unclear.
    OBJECTIVE: To compare the effect of low-concentration thrombin and standard-concentration thrombin on the prevention of cerebrospinal fluid leakage from dural injuries by fibrin glue.
    METHODS: Forty patients including 25 males and 15 females with dural injuries admitted at Fifth People’s Hospital of Chengdu from May 2017 to December 2019 were enrolled. Patients were randomly divided into two groups, 20 patients in each group. In low-concentration thrombin group, dural injuries were sealed with fibrin glue prepared with low-concentration thrombin solution (100 IU/mL). In standard-concentration thrombin group, dural injuries were sealed with fibrin glue prepared with standard-concentration thrombin solution (500 IU/mL). All patients were followed up for 2 months. The incidence of cerebrospinal fluid leakage, cumulative drainage flow, drainage duration and incision complications were compared between the two groups. The study was approved by Ethics Committee of Fifth People’s Hospital of Chengdu. 
    RESULTS AND CONCLUSION: (1) The incidence of cerebrospinal leakage, accumulative volume and duration of drainage in the low-concentration thrombin group were lower than those of standard-concentration thrombin group (P < 0.05). (2) Incision complications occurred in one case and secondary surgical drainage occurred in one case in the low-concentration thrombin group. Incision complications occurred in two cases and secondary surgical drainage occurred in two cases in the standard-concentration thrombin group. The incision complications and secondary surgical drainage were not statistically significant between the two groups (P > 0.05). (3) These results indicate that fibrin glue prepared with low-concentration thrombin solution decreases the rate of cerebrospinal leakage, reduces the drainage volume and shortens the duration of drainage, which is demonstrated to be an effective strategy for sealing dural injuries. 
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    Immobilization of lactase on magnetic chitosan microspheres and its effect on enzymatic properties
    Li Li, Ma Li
    2021, 25 (4):  576-581.  doi: 10.3969/j.issn.2095-4344.2372
    Abstract ( 265 )   PDF (791KB) ( 59 )   Save
    BACKGROUND: The free enzyme has the problems of poor stability and inability to be reused during application. Using magnetic polymer microspheres as the carrier of the binding enzyme to prepare immobilized enzyme can maintain the natural activity of the enzyme, and can be reused, but also provide convenient conditions for automatic production management.
    OBJECTIVE: Magnetic chitosan microspheres as carrier of binding enzyme were used to prepare the immobilized lactase, which is easy to recycle, can be reused, and has high enzyme activity and stability.
    METHODS: By inputting a certain amount of magnetic chitosan microspheres into the phosphoric acid buffer for swelling for 2 hours, the swelling magnetic chitosan microspheres were collected with a magnet and added to a certain concentration of lactase phosphate buffer. They were shocked in a constant temperature shaker for 1 hour and preserved in refrigerator at 4 °C. The microspheres were precipitated with a magnet to pour out the supernatant. After full washing with buffer solution, the immobilized lactase was obtained. The properties of the magnetic microspheres (the amount of glutaraldehyde used in the preparation of microspheres was 2, 4, 6, 8, 10, 12, 14 mL), the amount of enzymes (0.5, 1, 1.5, 2 g/L) added, the pH (6.4, 6.8, 7.0, 7.2) of the buffer, and the immobilization time (1, 2, 5, 10, 15, 20 hours) were tested to determine the optimal immobilization conditions.
    RESULTS AND CONCLUSION: (1) The optimum conditions for immobilized lactose with magnetic chitosan microspheres were as follows: magnetic chitosan microspheres prepared with 10 mL of glutaraldehyde were selected as the immobilized carrier of lactase. The amount of enzyme added was 0.3 g/L, pH 7.0 and the immobilization time was 5 hours. (2) Compared with the free enzyme, immobilized lactase showed a wider range of reaction temperature and pH value. (3) The ability of immobilized enzyme binding substrate was enhanced. (4) After repeated use of the immobilized enzyme five times, the enzyme activity remained 65%. (5) The storage stability of lactase was also improved after immobilization.
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    Tendon-bone healing in anterior cruciate ligament reconstruction with and without remnant preservation
    Ma Ziyue, Ju Xiaochen, Zhang Lei, Sun Rongxin
    2021, 25 (4):  582-587.  doi: 10.3969/j.issn.2095-4344.2373
    Abstract ( 254 )   PDF (974KB) ( 29 )   Save
    BACKGROUND: Whether remnant preservation can improve tendon-bone healing remains a controversy. Experiments were designed to evaluate whether remnant preservation has the biological advantage of promoting tendon-bone healing by histology and imaging. 
    OBJECTIVE: To investigate the effect of preservation of ligament stump on tendon-bone healing in anterior cruciate ligament reconstruction. 
    METHODS: Forty New Zealand rabbits were randomly divided into two groups: anterior cruciate ligament reconstruction group without remnant preservation (group A) and anterior cruciate ligament reconstruction group with remnant preservation (group B), with 20 rabbits in each group. Achilles tendon was selected as the graft, and the bilateral anterior cruciate ligaments of all the rabbits were cut off. In group A, the anterior cruciate ligament stump was completely removed. In group B, the tibia stump was cut off from the femoral stop, and the tibia stump was retained. According to the position of the anterior cruciate ligament of the normal rabbits, the tibia and the femoral canal were selected for reconstruction. At 6 and 12 weeks after surgery, the expression of vascular endothelial growth factor and hypoxia inducible factor-1α was detected by immunohistochemistry. Graft microvessel density was detected by CD34 immunohistochemical staining. The signal intensity of tendon and the width of bone tunnel were observed by MRI and CT.  
    RESULTS AND CONCLUSION: (1) The percentage of hypoxia inducible factor-1α and vascular endothelial growth factor positive cells in group B was significantly higher than that in group A at 6 weeks after operation (P < 0.05). The microvessel density in group B was significantly higher than that in group A (P < 0.05). At 12 weeks after operation, the percentage of hypoxia inducible factor-1α and vascular endothelial growth factor positive cells in the two groups decreased 12 weeks after operation compared with that in the same 6-week group (P < 0.05). The microvessel density in the two groups increased 12 weeks after operation compared with that in the same 6-week group (P < 0.05), and there was no significant difference between the two groups (P > 0.05). (2) At 6 weeks after operation, the expansion of bone tunnel in group B was significantly lower than that in group A, and the signal intensity of tendon graft was lower in group B than that in group A (P < 0.05). After 12 weeks, the expansion degree of bone tunnel and the signal intensity of tendon were decreased in both groups (in the same group P < 0.05, between the two groups P > 0.05). (3) In this experiment, in the early stage of ligament reconstruction, the anterior cruciate ligament reconstruction with remnant preservation is superior to the anterior cruciate ligament reconstruction without remnant preservation in terms of graft revascularization and reduction of bone tunnel expansion, showing some biological advantages.
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    Blood compatibility of disposable blood perfusion device in vitro
    Xu Jianxia, Wang Zhaoxu, Wang Chunren
    2021, 25 (4):  588-592.  doi: 10.3969/j.issn.2095-4344.2345
    Abstract ( 275 )   PDF (644KB) ( 30 )   Save
    BACKGROUND: As a medical device that is in contact with circulating blood in a large area for a long time, blood compatibility testing of the blood perfusion device is very important. 
    OBJECTIVE: To test the blood compatibility of the test blood perfusion device.
    METHODS: The resin microparticles in the test blood perfusion device and the marketed blood perfusion device (as a control) were mixed with human anticoagulated blood respectively, and placed on a 37 °C rotating incubator for hematology, platelet, coagulation and complement detection in vitro. The two kinds of resin microparticles were respectively contacted with rabbit semi-anticoagulated blood, and the degree of thrombosis was compared by detecting the remaining fibrinogen content in the plasma. The two resin microparticles were placed in physiological saline, and then diluted anticoagulated rabbit blood was added for hemolysis experiment. The animal experiment was approved by the Ethics Committee of National Institutes for Food and Drug Control.
    RESULTS AND CONCLUSION: (1) The activated partial thromboplastin time and platelet concentration of the test blood perfusion device resin particle group were greater than those of the control perfusion device resin particle group (P < 0.01), and the total complement activity was lower than that of the control perfusion device resin particle group (P < 0.01). There was no statistically significant difference in prothrombin time, fibrinogen, the number of leukocytes and erythrocytes between the two groups (P > 0.05). (2) In the thrombosis test, there was no statistical difference in the concentration of fibrinogen between the two groups (P > 0.05). (3) The hemolysis rate of the resin microparticles in the test blood perfusion device was 0.2%. (4) The results showed that compared with the resin microparticles in the control perfusion device, the resin microparticles in the test blood perfusion device activated the complement and the coagulation system more severely (relative percentage to the control between 85%-115%), but the effect on the number of platelets is relatively small; the hemolysis rate of the resin particles in the test blood perfusion device is low; and its blood compatibility is acceptable.
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    Comparison of tantalum and titanium (alloy) as orthopedic materials: physical and chemical indexes, antibacterial and osteogenic ability
    Shi Xiaoxiu, Mao Shilong, Liu Yang, Ma Xingshuang, Luo Yanfeng
    2021, 25 (4):  593-599.  doi: 10.3969/j.issn.2095-4344.2374
    Abstract ( 612 )   PDF (663KB) ( 49 )   Save
    BACKGROUND: Tantalum and titanium (alloy) are the most widely employed metallic biomaterials in orthopedics. Tantalum is especially focused because of its excellent corrosion resistance and osteointegration. However, whether tantalum is better than titanium (alloy) as orthopedic materials is still in dispute.
    OBJECTIVE: To review the comparative studies on the biological performances of tantalum and titanium (alloy) and analyze the possible causes of the similarities and differences of biocompatibility of tantalum and titanium (alloy) materials in vivo and in vitro.
    METHODS: A computer-based search of CNKI, Wanfang and PubMed database was performed for articles relating to the comparative studies on the biological performances of tantalum and titanium (alloy) published until January 2020. The search words were “tantalum” in title and “titanium” in title or abstract, i.e., (tantalum[Title])) AND (titanium[Title/Abstract]). 
    RESULTS AND CONCLUSION: Among the comparative studies on the biological performances of tantalum and titanium (alloy), two viewpoints were primarily involved according to the results from clinical follow-up, animal tests, and cellular experiments. One is that tantalum is superior to titanium (alloy) with better osteogenesis and bone formation and stronger antibacterial activity, while the other one is that tantalum has similar osteogenesis and bone formation and antibacterial activity to titanium (alloy). The primary reason responsible for this divergence is that the fabrication method and the surface chemistries, topographical structures or pore structures are different between the employed tantalum and titanium (alloy).
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    Material selection, theoretical design and biomimetic function of artificial periosteum
    Chang Wenliao, Zhao Jie, Sun Xiaoliang, Wang Kun, Wu Guofeng, Zhou Jian, Li Shuxiang, Sun Han
    2021, 25 (4):  600-606.  doi: 10.3969/j.issn.2095-4344.2375
    Abstract ( 362 )   PDF (965KB) ( 80 )   Save
    BACKGROUND: Periosteum, as the storage site and recruitment scaffold of progenitor cells and growth factors, plays an important role in the blood supply of bone tissue and the formation and regeneration of bone. Thus, it has become a research hotspot in recent years to develop an artificial periosteum material which can simulate natural periosteum both in structure and function.
    OBJECTIVE: To review the research progress of artificial periosteum material and its application in clinical treatment.
    METHODS: The relevant documents published by PubMed database up to February 2020 were searched by computer with the search term of “periodium, tissue engineering, artificial, regeneration, repair”.
    RESULTS AND CONCLUSION: The artificial periosteum simulates the structure and function of natural periosteum through three elements: scaffolds, cells and factors, which provide a new possibility for the clinical treatment of periosteal tissue repair and bone regeneration. At present, the artificial periosteum can be divided into cell-sheet periosteum material, acellular-scaffold periosteum material and artificially synthetic scaffold periosteum material. Cell-sheet artificial periosteum is relatively simple to prepare and is a kind of tissue engineering periosteum material which has been put into clinical use earlier. Acellular-scaffold artificial periosteum can keep its natural structure or element to the greatest extent. The material of artificially synthetic scaffold is rich and convenient, and has a low incidence of anti-rejection. These materials all showed good osteogenic effect. However, at present, the bionic research on the structure and function of artificial periosteum is still in its infancy, and further improvement is still needed in material selection, theoretical design and other aspects, so as to make it more mature in biological bionic function.
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    Characteristics and manufacturing techniques of collagen/inorganic materials for constructing tissue-engineered bone
    Liu Liu, Zhou Qingzhu, Gong Zhuo, Liu Boyan, Yang Bin, Zhao Xian
    2021, 25 (4):  607-613.  doi: 10.3969/j.issn.2095-4344.2376
    Abstract ( 225 )   PDF (650KB) ( 35 )   Save
    BACKGROUND: At present, the standard method for clinical treatment of bone defects is autologous bone transplantation. However, the source of autologous bone is limited and it can cause new trauma and defects. Therefore, the development of ergonomic tissue-engineered bone has become the trend of repairing bone defects. 
    OBJECTIVE: To summarize the characteristics and manufacturing techniques of collagen/inorganic materials to construct tissue-engineered bone.
    METHODS: PubMed, Web of Science (January 2000–January 2020) and CNKI (2010–2020) databases were used online to retrieve the relative articles regarding the application of collagen/inorganic composite scaffold. The key words were “collagen; inorganic materials; tissue-engineered bone; bone repair; geometry of bone scaffold” in English and Chinese, respectively.  
    RESULTS AND CONCLUSION: Applying the principle of bionics, collagen composite inorganic materials were used to construct tissue-engineered bones by simulating the composition, structure, and characteristics of natural bones, which is an important direction in the field of bone graft materials. Collagen provides the extracellular matrix effect of the scaffold material, and promotes the migration, adhesion, and proliferation of cells on the scaffold, and accelerates the degradation of the scaffold in the body, and makes the composite scaffold has good biocompatibility and osteoinductivity. Choosing a suitable manufacturing technology to change the geometry of the collagen/inorganic material scaffold, and achieving the best three-dimensional porous nanoscale structure can promote cell adhesion and proliferation, and enhance the bone regeneration capacity of collagen/inorganic material scaffolds. Simultaneously, the surface of collagen/inorganic scaffolds is modified. Stem cells, biological factors, and polymers with osteogenic or angiogenic potential were compounded onto collagen/inorganic material scaffolds, which will improve the poor mechanical properties, insufficient structural stability, and limited bone regeneration capacity of collagen/inorganic material scaffolds. This provides a good idea for the option of tissue-engineered bone graft materials.
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    Advantages and problems of local antibiotic delivery system in the treatment of osteomyelitis
    Liu Fei, Cui Yutao, Liu He
    2021, 25 (4):  614-620.  doi: 10.3969/j.issn.2095-4344.2332
    Abstract ( 351 )   PDF (774KB) ( 37 )   Save
    BACKGROUND: Local antibiotic delivery system can increase local drug concentration, reduce drug toxicity, and increase drug bioavailability, thereby improving the antibacterial efficacy and providing a new method for the long-term treatment of osteomyelitis.
    OBJECTIVE: To summarize the application progress of various local drug sustained-release systems in the treatment of osteomyelitis, and analyze the current deficiencies and research directions.
    METHODS: The authors searched for related articles in PubMed, Web of Science, Medline, Wanfang and CNKI databases published from 2007 to 2020. The key words were “osteomyelitis, drug delivery system, antibiotics, PMMA, degradable material” in English; and “osteomyelitis, drug release system, PMMA, degradable materials” in Chinese. There were 221 preliminary inspection articles, and 76 articles were analyzed after screening.
    RESULTS AND CONCLUSION: Currently, carrier materials commonly used in local drug release systems include degradable materials such as collagen, bioactive glass, and non-degradable materials such as PMMA bone cement. Non-biodegradable antibiotic carriers have been successfully used clinically, but these carriers need to be removed by a second operation, and their early explosive drug release will have a great impact on their efficacy. Therefore, further research on the improvement of non-degradable materials is needed to better improve their efficacy. The local antibiotic delivery system of biodegradable materials can not only continuously deliver drugs at the infection site, but also act as bone filling materials in the early stage. Some degradation products can even create a good bone conduction environment for blood vessels and new bone formation. However, the precise control of drug release in complex systems requires further research.
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    Role and mechanism of hierarchical microchanneled bone scaffolds in promoting osteogenesis and angiogenesis
    Ye Haimin, Ding Linghua, Kong Weihao, Huang Zutai, Xiong Long
    2021, 25 (4):  621-625.  doi: 10.3969/j.issn.2095-4344.2377
    Abstract ( 268 )   PDF (674KB) ( 49 )   Save
    BACKGROUND: How to recruit endogenous seed cells to promote osteogenesis, provide appropriate bone regeneration microenvironment for cells and ensure the vascularization process of new bone are the difficulties of bone tissue engineering research.
    OBJECTIVE: To review the osteogenesis and vasculogenesis from the aspects of hierarchical microchanneled bone scaffold.
    METHODS: The first author searched relevant literature on the promoting effect of hierarchical microchanneled bone scaffold on osteogenesis and angiogenesis from China National Knowledge Infrastructure, Wanfang, PubMed and Web of Science databases from 1950 to 2020. The key words were “hierarchical microchanneled scaffolds, osteogenesis, and angiogenesis” in Chinese and English. Finally, a total of 52 articles meeting the inclusion criteria were selected.  
    RESULTS AND CONCLUSION: Hierarchical microchanneled bone scaffold has a good role in promoting osteogenesis and vascularization, and has a good application prospect in bone tissue engineering. At present, hierarchical microchanneled bone scaffold is mature in the theory of bone tissue engineering. In vitro experiments have confirmed that the hierarchical microchanneled bone scaffold can promote the adhesion and differentiation of mesenchymal stem cells into osteoblasts, but the osteogenic effect in vivo is still poor, and it is still possible to further improve the osteogenic effect. In the future, we should focus on the construction of hierarchical microchanneled bone scaffold complexes, such as chemokines or cytokines, which can further improve the osteogenic efficiency in vivo.
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    Application of bone tissue engineering materials in the treatment of bone defect diseases in vivo
    Li Xiaozhuang, Duan Hao, Wang Weizhou, Tang Zhihong, Wang Yanghao, He Fei
    2021, 25 (4):  626-631.  doi: 10.3969/j.issn.2095-4344.2378
    Abstract ( 253 )   PDF (647KB) ( 80 )   Save
    BACKGROUND: The application of bone tissue engineering materials to treat bone defect diseases is a hot topic of current research. Material selection and design of in vivo experiments are the focus of research.
    OBJECTIVE: To summarize the research progress of bone tissue engineering materials for repairing bone defects in vivo in the past 10 years.
    METHODS: A search was conducted in CNKI, Wanfang, and PubMed with the key words of “bone tissue engineering, bone defect and in vivo experiment” for articles published from January 2010 to December 2019. Totally 264 articles were retrieved, and 74 eligible articles were finally summarized after screening.
    RESULTS AND CONCLUSION: Bone tissue engineering is a new method for treating bone defect diseases, but there are many types of bone tissue engineering materials in practical application. The single material inevitably has limitations in the application of materials. Composite materials can improve material properties and bone repair capacity. Simultaneously, the in vivo experiment is a powerful test to verify the practical application of the material, and it can detect the shortcomings that were not found in the in vitro experiments, and provide data support for the practical application of bone tissue engineering materials. 
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    Development prospect of orthopedic rehabilitation medicine based on three-dimensional printing technology
    Peng Kun, Lin Yimin, Gan Xiaoling, Wu Zhiyong
    2021, 25 (4):  632-637.  doi: 10.3969/j.issn.2095-4344.2333
    Abstract ( 316 )   PDF (872KB) ( 55 )   Save
    BACKGROUND: The application of three-dimensional (3D) precision printing in orthopedic rehabilitation medicine is attracting more and more attention from clinicians, engineers and researchers.
    OBJECTIVE: To review the development of 3D printing in orthopedic rehabilitation.
    METHODS: Relevant documents published from 2011 to 2019 were retrieved from CNKI database, Wanfang database, PubMed database and Elsevier database by computer. The search terms were “3D Precision Printing, Orthopedic rehabilitation medicine, Artificial Intelligence” in English and Chinese.  
    RESULTS AND CONCLUSION: At present, 3D precision printing is the key technology in the application of orthopedic rehabilitation medicine, including medical image processing and 3D modeling, surgical simulation planning system, surgical guide board design, implant design and 3D precision printing equipment. Among them, 3D reconstruction technologies such as multiplanar reconstructions, volume rendering technique, maximum intensity projection, minimum intensity projection and surface shaded display are used to read medical digital data and realize visual medical image processing and 3D modeling, which can improve doctor-patient communication efficiency. The thinking process and intelligent behavior of doctors in rehabilitation surgery can be simulated by computer, and a cloud service center with function similar to the brain intelligence of doctors is created to assist doctors in the planning of rehabilitation surgery. With the aid of personalized rehabilitation surgery guide board design software, the bone graft osteotomy guide board can be used to plan the osteotomy line and osteotomy range for the doctor, which can shorten the operation time and improve the operation safety. Using polymer materials, metal materials, ceramic materials and other materials as 3D printing materials, there are still problems such as poor mechanical adaptation and physiological adaptation. The automation degree of common biological 3D design software is relatively low, which is prone to problems such as unsatisfactory matching between the performance of orthopedic medical devices and the defect site, and single internal pore structure of implants. However, the application of 3D precision printing technology in the immersion rehabilitation medicine teaching system is beneficial to the cultivation of rehabilitation medicine talents combining with interdisciplinary medical workers.
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    Application of alginate based hydrogels/dressings in wound healing: sustained, dynamic and sequential release
    Zhang Zhenkun, Li Zhe, Li Ya, Wang Yingying, Wang Yaping, Zhou Xinkui, Ma Shanshan, Guan Fangxia
    2021, 25 (4):  638-643.  doi: 10.3969/j.issn.2095-4344.2379
    Abstract ( 386 )   PDF (661KB) ( 235 )   Save
    BACKGROUND: Alginate can improve the hydrophilic quality of wound dressing, create moist wound microenvironment, and remove wound exudate. Currently, alginate bimolecular materials have been used in the design and development of various wound dressings to improve the efficiency of wound healing.
    OBJECTIVE: To summarize the research and progress of alginate based hydrogels/dressings in skin wound healing.
    METHODS: We searched PubMed, Science Direct and CNKI databases from 2000 to 2020 with the English terms of “alginate hydrogel, wound healing, wound dressing, mesenchymal stem cell, growth factor, nanoparticles, diabetic wound, antibiotics, bioactive peptide, three-dimensional printing” and the Chinese terms of “alginate, wound healing”. Based on the inclusion and exclusion criteria, 60 articles were finally reserved for review. 
    RESULTS AND CONCLUSION: (1) The cross-linking of alginate with other organic or inorganic materials can improve the mechanical properties and biodegradability of composite materials, and create a moist and mild wound microenvironment. (2) Alginate based hydrogel/dressing can be used as a delivery platform to load seed cells, growth factors or other bioactive substances to speed up wound healing. (3) It still need to be further explored by researchers to make alginate materials have better cell recognition sites, improve the mechanical properties of composite scaffold materials, control the microstructure of alginate biomaterials and control the dynamic, sustained and sequential release of drugs or cells.
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    Tissue engineering scaffolds in repairing oral and maxillofacial soft tissue defects
    Chen Jiana, Qiu Yanling, Nie Minhai, Liu Xuqian
    2021, 25 (4):  644-650.  doi: 10.3969/j.issn.2095-4344.2380
    Abstract ( 280 )   PDF (660KB) ( 55 )   Save
    BACKGROUND: In recent years, more and more scaffold materials have been used to repair soft tissue defects, and the clinical repair effect of soft tissue defects is strongly associated with the source and performance of materials.
    OBJECTIVE: To summarize the research progress of preparation and application of different biological scaffolds in the field of oral and maxillofacial soft tissue defect repair.
    METHODS: PubMed and Medline were searched for articles published from 1966 to 2019 with the English key words of “materials, scaffold, biological scaffold, soft tissue, coloboma, tissue engineering, review”. Chinese journal full-text database and Chinese science citation database were retrieved for articles published from 2003 to 2019 with key words of “material, scaffold, biological scaffold, soft tissue, defect, tissue engineering, review”.  
    RESULTS AND CONCLUSION: Natural bio-scaffold materials are directly derived from organisms with pretty biocompatibility. Natural bio-scaffold materials can release cytoactive factors, promote cell adhesion, proliferation and differentiation, and can be combined with synthetic polymer materials with controllable properties to form composite scaffolds, which is an ideal scaffold material for repairing soft tissue defects of oral and maxillofacial regions. Nanomaterials have higher biological activity than other scaffold materials and can promote the adhesion and proliferation of seed cells, providing ideal three-dimensional space for cell growth, but their applications are currently mainly reflected in bone tissue repair, and the applications in soft tissue repair are very few. At present, there are many researches on natural biological scaffold materials in oral and maxillofacial soft tissue repair, mainly including small intestinal submucosa, acellular dermal matrix and acellular vascular scaffolds. The combination of natural biological scaffold materials and synthetic polymer materials will be a major research trend in materials for repairing oral and maxillofacial soft tissue defects.
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    Microenvironment and repair methods of peripheral nervous system injury
    Song Kaikai, Zhang Kai, Jia Long
    2021, 25 (4):  651-656.  doi: 10.3969/j.issn.2095-4344.2850
    Abstract ( 359 )   PDF (705KB) ( 42 )   Save
    BACKGROUND: Peripheral nerve injury has been very common in clinical work. Although microsurgical technique can restore the continuity of the injured nerve well, the nerve repair effect is still unsatisfactory due to the high degree of differentiation and low regeneration ability of the peripheral nerve tissue, which seriously affects the quality of life of patients. At present, there is no unified conclusion on the microenvironment of peripheral nerve injury, and there are many repair methods in common use.
    OBJECTIVE: To review the microenvironment of peripheral nerve injury and the repair methods of peripheral nerve injury.
    METHODS: A computer-based online search of PubMed and CNKI databases was performed for the articles published from January 1964 to September 2019. The key words were “peripheral nerve injury; microenvironment; microsurgical technique; small gap bridging” in English and Chinese, respectively. Finally, 57 eligible articles were included to review. 
    RESULTS AND CONCLUSION: (1) After a series of animal experiments and clinical studies, changes in microenvironment such as the establishment of nerve regeneration channels, neurotrophic factors, immune response, inflammatory response, and hormone regulation have been confirmed to be important factors affecting peripheral nerve repair. (2) It is feasible to repair the peripheral nerve injury by using biological conduit small gap bridging instead of the traditional external and fascicular membrane.
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