RESUMO
Objective To develop a new method, the bone marrow stromal cells (BMSCs)-mediated tissue engineering technique combined with mosaicplasty, for repair of osteochondral defects and integration of gaps. Methods BMSCs from 12 Chinese goats were cultured and proliferated in vitro. Prior to the BMSCs harvest, osteochondral defects, 5 mm in diameter and 3 mm in depth, were created in the femoral medial condyles of both the goat's hind limbs. When the mosaicplasty (osteochondral autograft transplantation) was performed, the BMSCs, which had been harvested and compounded with hyaluronic acid, were injected into the gaps between the osteochondral autografts in the left hind limb. The right hind limb which only received osteochondral autograft transplantation without BMSCs served as a control. At four, eight and 16 weeks post-operatively, samples of the repaired defects were harvested and assessed by histological evaluation, immunohistochemical analysis and glycosaminoglycan (GAG) quantification. In both groups 16 weeks post-operatively, the GAG quantification was analyzed by one-way ANOVA and least significant difference (LSD) method. Results At all the time points, the cartilage autografts in both groups survived as hyaline cartilage and presented no significant difference from the surrounding native cartilage. In the group filled with BMSCs compound, the gaps were replaced by regenerated hyaline cartilage and disappeared; however, in the control group, the osteochondral autografts were still distinct from the surrounding normal cartilage, though the gaps were replaced by fibrous tissue or fibrous cartilage. Immunohistochemical analysis of typeⅡcollagen showed positive staining in the matrix of transplanted and regenerated cartilage. The Alcian blue method also confirmed a significantly less GAG content in the regenerated tissue in gaps in the control group than in the treatment group and in the normal cartilage. Conclusion Since tissue engineering combined with mosaicplasty can promote gap integration and cartilage healing, the method can be an ideal way for osteochondral defect repair.