Objective To investigate the feasibility of cartilaginous implantscontaining bone marrow stromal cells(MSCs) derived from chondrocytes in biological resurfacing procedures for repairing articular cartilage defect. Methods MSCs derived from chondrocytes were obtained with high initial cell density subculture. An implant was constructed by dispersing the chondrocytes in a acid soluble type Ⅰ collagen gel(5×106cells/ml, final cell concentration). A fullthickness defect 3 mm×5 mm was created in the trochlear groove of femur in 36 rabbits. A piece of cotton soaked in 0.5% trypsin was laid into the defect for 5 minutes, then the defect was filled with MSC/collagen gel implant on one side(n=36), filledwith a plain collagen gel on the other side(n=18),and left empty as controls on the other side(n=18). The animals were sacrificed at 4, 8, 12, 24, 32,and 48 weeks. The repaired tissue was examined and evaluated with Pineda gradingscale. Results In MSCs group, the implanted cells resembled well differentiated chondrocytes and were surrounded by metachromatic matrix and the reparative tissue resembled hyaline cartilage after 4 weeks; bone was formed at the base of the defects, the thickness of new cartilage was larger than tht of normal one after 8 weeks; the thickness was reduced proximally, approximating to that of normal cartilage, and chondrocyte columns was formed and subchondral bone and tidemark reappeared after 12 weeks; the thickness of the new tissue was about 55% of the normal tissue, with smooth surface and there were hypertrophic chondrocytes near the tidemark after 24 weeks; no hypertrophic chondrocytes were observed, indicating cessation of endochondral ossification after 32 weeks; the tissue architecture was the same as that at 32 weeks, hyaline-like cartilage persisting, with subchondral bone and tidemark in continuity after 48 weeks. The four layer cell orientation was not as clear as that of normal cartilage. The defects were partially filled with fibrous tissue in controls. At 32 weeks, erosive cartilage, naked subchondralbone and proliferative synovial membrane indicated the presence of osteoarthrosis. There were no statistical difference according to Pineda tissue scales in the specimens from the MSCs group between 24, 32, and 48 weeks, but there was significant difference between 4 weeks and 24, 32 and 48 weeks (Plt;0.05). The joint function recovered after 2 weeks in MSCs group, while it deteriorated progressively incontrols. Conclusion MSCs derived from chondrocytes improve repair of largefullthickness defect in articular cartilage. The reparative hyaline-like cartilage is stable differentiation after 24 weeks, maintains good joint function after 48 weeks.
Objective To review the study progress of mesenchymal stem cells induced to differentiate intervertebral disc cells Methods The recent related literature was reviewed. The theorical and experimental studies were summarized. Results MSCs had the potential of multidirectional differentiation.International experimental studies indicated the potential of MSCs induced to differentiate intervertebral disc cells. Conclusion MSCs induced to differentiate intervertebral disc cells has the fine prospect.
ObjectiveTo investigate the clinical outcome of application of joint prosthesis in limb salvage treatment of mildmalignant tumor at the articular ends of femurs, with severe osteolysis. Methods The treatment of 15 cases of mildmalignant tumor at the articular ends of femurs with severe bone destruction, from 1978 to 1999, was reviewed. There were 10 cases of giant-cell bone tumor and 5 cases of chondrosarcoma, among which there were 5 cases at the stage ofⅠA, 9 cases at ⅠB, and 1 case at ⅡA, with 4 cases at the proximal end and 11cases at the distal end. The tumor was totally removed, with a massive bone defect left at the foci, and then the prosthesis replacement was performed to reconstruct the articular joint. All of the 15 patients were followed up for 9 monthsto 20 years, 4 years and 3 months on average, before clinical evaluation. Results All of the wound healed well, with primary healing. Local relapse occurred in one case and the patient died of lung metastasis; the amputation of the replaced knee joint was performed in one case due to severe infection after trauma; radiograph showed there was slight sunk of the prosthesis in 2 cases after replacement. The other 11 cases recovered well with satisfactory function. Conclusion The limb salvage treatment of mildmalignant tumor at the articular ends of femurswould be available, especially for those with massive bone destruction, when the tumor is removed by whole and rationally marginal resection, followed by properlyutilization of prosthesis and general post-operative exercise.