Isolated co-culture of bone mesenchymal stem cells and auricular chondrocytes to construct cartilage

Objective To explore the feasibility of chondrogenesis by isolated co-culture of BMSCs and chondrocytes so as to confirm the hypothesis that chondrocytes can provide chondrogenic differentiation of BMSCs.Methods Rabbit BMSCs(5.0×107/ml) were seeded onto a polyglycolic acid/polyactic acid(PGA/PLA) scaffold.The cell-scaffold constructs were put into a transwell,under transwell were adherent chondrocytes,as experimental group.The control group had no adherent chondrocytes under transwell(containing 10% fetal calf serum).All specimens were harvested after in vitro culture for 8 weeks and implanted subcutaneously in the dorsum of athymic nude mice for 6 weeks.Gross observation,RT-PCR,histology and immunohistolochemistry were used to evaluate the results.Results In experimental and control groups,the cells adhered to the scaffold well and produced abundant extracellular matrices after one week of in vitro culture.RT-PCR shows type Ⅱ collagen and aggrecan demonstrate stronger expression in experimental group,while that express little in control group after 8 weeks of in vitro culture,which suggest BMSCs in experimental group underwent chondrogenic differentiated stage.After 6 weeks of subcutaneous implantation into nude mice,specimen in experimental group could form cartilage-like tissue with typical cartilage lacuna,and maintain the original size and shape.The cell-scaffold constructs in control group shrunk gradually and could not form cartilage.The results were further supported by histological feature and immunohistochemistry.Conclusion Chondrocytes can promote the chondrogenesis of BMSCs by isolated coculture.