Objective To explore the osteogenesis and angiogenesis effect of bone marrow mesenchymal stem cells (BMSCs) derived osteoblasts and endothelial cells compound with chitosan/hydroxyapatite (CS/HA) scaffold in repairing radialdefect in rats. Methods The BMSCs were isolated from Sprague Dawley rats and the 3rd generation of BMSCs were induced into osteoblasts and endothelial cells. The endothelial cells, osteoblasts, and mixed osteoblasts and endothelial cells (1 ∶ 1) were compound with CS/HA scaffold in groups A, B, and C respectively to prepare the cell-scaffold composites. The cell proliferation was detected by MTT. The rat radial segmental defect model was made and the 3 cell-scaffolds were implanted, respectively. At 4, 8, and 12 weeks after transplantation, the graft was harvested to perform HE staining and CD34 immunohistochemistry staining. The mRNA expressions of osteopontin (OPN) and osteoprotegerin (OPG) were detected by RT-PCR. Results Alkal ine phosphatase staining of osteoblasts showed that there were blue grains in cytoplasm at 7 days after osteogenic induction and the nuclei were stained red. CD34 immunocytochemical staining of the endothelial cells showed that there were brown grains in the cytoplasm at 14 days after angiogenesis induction. MTT test showed that the proliferation level of the cells in 3 groups increased with the time. HE staining showed that no obvious osteoid formation, denser microvessel, and more fibrous tissue were seen at 12 weeks in group A; homogeneous osteoid which distributed with cord or island, and many osteoblast-l ike cells were seen in groups B and C. The microvessel density was significantly higher in groups A and C than group B at 3 time points (P lt; 0.05), and in group A than in group C at 12 weeks (P lt; 0.05). The OPN and OPG mRNA expressions of group A were significantly lower than those of groups B and C at 3 time points (P lt; 0.05). In groups B and C, the OPN mRNA expressions reached peak t8 and 12 weeks, respectively, and OPG mRNA expressions reached peak at 4 weeks. Conclusion BMSCs derived steoblasts and endothelial cells (1 ∶ 1) compound with CS/HA porous scaffold can promote bone formation and vascularization in bone defect and accelerate the healing of bone defect.
Objective To investigate the clinical application and complicationof the lyophilized small-segment allogeneic bone used in repairing bone defectscaused by benign bone tumor and tumor-like lesions after resection and curettage. Methods From December 1999 to December 2005, 230 patients (156 males, 74 females; age, 5-56years, averaged 32.8 years), who had bone defects caused by benign bone tumors and tumor-like lesions after surgical resection and curettage, were treated by the lyophilized small-segment allogeneic bones. The cavities left by the tumor curettage ranged in size from 1.0 cm×0.8 cm to 10.0 cm×2.0 cm, andthe bone defects were about 1.0 to 3.5 cm in diameter after the localized resection of the bones. According to the bone defect degrees, the autogenous nonvascular iliac bone and the bone allograft (0.5-30.0 g) were implanted, followed by the drainage for 2-3 days and the use of antibiotics to prevent infection. The postoperative systemic and local reactions were observed, and the regular X-ray examinations were performed to observe the bone union. ResultsThere was no significant difference in the allergic reactions, such as postoperative temperature, drained amount, and body swelling, between this kind of transplantation and the autogenous bonetransplantation. The wounds in 196 patients were healed by the first intension.The wounds in 34 patients had extravasate. Among them, the wound was healed by changing dressing in 30cases; the wound had delayed healing in 4, including 3 whose wounds were healedby changing dressing for 3-4 weeks,and 1 whose wound was healed by taking out the implants. The follow-up for 6-60 months (average, 38 months) revealed that all the patients had the allograft unions of the bones within 6-18 months after the transplantation, and only 6patients had recurrence of the tumor (3.0%). Evaluated by the Mankin,Komender and WANG Zhiqiang’s standards, 196 (85.22%) patients were satisfied with their outcomes while the other 34 (14.78%) patients were not satisfied. Conclusion The lyophilized small-segment allogeneic bone has a good compatibility and osteogenesis, when it is used in repairing bone defects caused by benign bone tumor and tumor-like lesions after resection and curettage. So, this kind of bone is a good, convenient and safe material for the bone transplantation. The important factors affecting the allograft union are as follows: the mechanical stability in the recipient region, local blood supply, and management of the bone cavity left by resection and curettage of the bone tumor.
Objective To investigate the research progress of drug-loaded antibacterial coating of orthopedic metal implants in recent years. Methods The recent literature on the drug-loaded antibacterial coating of orthopedic metal implants were reviewed. The research status, classification, and development trend of drug-loaded antibacterial coating were summarized. Results The drug-loaded antibacterial coating of orthopedic metal implants can be divided into passive release type and active release type according to the mode of drug release. Passive drug release coating can release the drug continuously regardless of whether the presence of bacteria around the implants. Active drug release coating do not release the drug unless the presence of bacteria around the implants. Conclusion The sustained and stable release of drugs is a key problem to be solved in various antibacterial coatings research. The intelligent antibacterial coating which release antibiotics only in the presence of bacteria is the future direction of development.