| The repairing of articular cartilage injury is one of the problems in orthopedics, which is not solved finely today. Traditional methods such as subchondral drilling, abrading and microfracture have some disadvantages. Autologous osteocartilage, periosteum or perichondrium have limited source, and their harvesting may cause additional trauma. The immunologic rejection with allotransplantation has been a great concern that is hard to deal with. In recent years, there has been majar advance in tissue engineering, which is expected to provide a new treatment method for repairing cartilage defect. This paper explores the possibility and related problems of repairing articular cartilage injury of rabbits using tissue engineering techniques in five respects. 1 The experimental study of inducing marrow stromal cells (MSC) to chondrocytesObjective: To explore the possibility of inducing MSC into chondrocytes with rhBMP-2 and high polymer hyaluronic acid in vitro. Methods: About 4-6ml of bone marrow were aspirated with 16-gauge puncture needles from bilateral femoral trochanters, and then primary culture and subcultures of MSCs were done. The cells were divided into an experimental group and a control group.In the experimental group, rhBMP-2 (100ng/ml) was added to culture medium and high polymer hyaluronic acid was spread on the bottom of culture flasks in advance. In the control group, the cells were cultivated and subcultured as usual. H.E staining, toluidine blue staining, alkaline phosphatase staining andas usual. H.E staining, toluidine blue staining, alkaline phosphatase staining and immunohistochemical staining were done for subcultured cells. After PLGA carriers were loaded with cells, they were implanted into thigh muscle of rabbits.The nodules thus formed were observed macroscopically and microscopically.Osteocalcin in culture medium was also assayed. Results: In the experimental group, toluidine blue staining and immunohistochemical staining (S-100 protein and collagen II) were positive for the passage cells, especially the third passage cells. After 3 weeks, chondral nodules formed in the thigh muscle.But in the control goup, immunohistochemical staining for collagen I and collagenIII were positive in individual cells. It was mainly fibrous tissue formed in the rabbit thigh muscle after implanting PLGA-cell composites. There was no osteocalcin in the culture medium. Conclusions: In this study, we successfully induced marrow stromal cells into chondrocytes with rhBMP-2 and high polymer hyaluronic acid. We believe that MSC-derived chondrocytes can be used as seed cells to repair articular cartilage defect by cartilage tissue engineering technigues.2 Biocompatibility studies on two different biomaterials combined with cultured bone marrow stromal cells in vitroObjective: To study the biocompatibility of two different biomaterials (PLGA and collagen sponge). By culturing bone marrow stromal cells(MSC) of rabbits with the biomaterials in vitro, we tried to see if the materials can be used as biomaterial scaffold in cartilage tissue engineering. Methods: After some 2-month old New Zealand rabbits had been anesthetized, about 4-6ml of bone marrow were aspirated with 16-gauge puncture needles from their bilateral femoral trochanters, washed and centrifuged twice with D-hanks liquid(1000rpm x 10min), suspended in DMEM medium containing 10% FBS, and then primary culture and subcultures of MSC were done. The cells of passage were inoculated in 24-hole culture plank with 1.5 x 104 cells and 1ml of DMEM in each hole. There were 3 groups of experiments: PLGA group, collagen sponge group and control group. Materials of 5mm in diameter and 2mm in thickness were used in the PLGA group and the collage sponge group respectively. In the control group,only cells were inoculated. The implanted cells and materials were retrieved and observed at different times with phase contrast microscope, scanning electron microscope.They also were assessed by growth curve and flow cytometry(FCM). Results: MSCs grew around PLGA and colla...
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