Bone Morphogenetic Protein-7 Induces Chondrogenic Differentiation in Human Mesenchymal Stem Cells Cultured on Tricalcium Phosphate-Collagen Scaffolds

Bone morphogenetic protein-7 (BMP-7) is one of the most promising growth factors in cartilage tissue engineering. However, the effect of exogenous BMP-7 on human mesenchymal stem cells (hMSCs) cultured on tissue engineering scaffolds is not clear. The objective of this study was to evaluate the role of BMP-7 in the chondrogenic differentiation of hMSCs cultured on tricalcium phosphate-collagen (TCP-COL) scaffolds in vitro. hMSCs were isolated and seeded on TCP-COL scaffolds. The hMSC-seeded scaffolds were then cultured in the absence or presence of BMP-7 (50 ng/mL and 100 ng/mL) for 2 weeks. hMSC distribution and matrix formation were monitored by histological staining and scanning electron microscopy analysis. Expression of genes and proteins involved in chondrogenic differentiation was investigated by sulfated glycosaminoglycan (GAG) quantification, immunohistochennical staining, histological staining, and qPCR. Cell death rate of hMSCs was assessed by TUNEL assay, and the results were compared with those obtained for the untreated group. Our results demonstrated that BMP-7 could induce chondrogenic differentiation of hMSC cultures on TCP-COL scaffolds, and that this effect increased in a dose-dependent manner. BMP-7 did not influence cell proliferation, but it did increase total GAG content. No obvious toxicity of high-dose of BMP-7 was detected in our study, suggesting that the TCP-COL scaffold, in combination with BMP-7, might represent a useful tool for cartilage tissue engineering.