Different doses of bone morphogenetic proteins-7 promote chondrogenesis of human mesenchymal stem cells in tricalcium phosphate-collagen scaffolds

Objective To investigate the effects of different doses of bone morphogenetic proteins-7 (BMP-7) on engineered cartilage formation. Methods Human mesenchymal stem cells (hMSCs) were isolated by density gradient centrifugation and then were seeded onto tricalcium phosphate-collagen scaffolds (TCP-COL). hMSCs were cultured on the scaffold for two weeks and divided into three experimental groups: (1) control group: chondrogenic medium (without TGF-β); (2) BMP-7 (50) group: chondrogenic medium (without TGF-β) with 50 ng/ml BMP-7; (3) BMP-7 (100) group: chondrogenic medium(without TGF-β) with 100 ng/ml BMP-7. The effect of BMP-7 on chondrogenesis was assessed by scanning electron microscopy (SEM) observation, hematoxylin-eosin (HE) staining, alcian blue staining, typeⅡ collagen immunohistochemical staining, RT-PCR and GAG quantification assay. Results BMP-7 could significantly induce the chondrogenic differentiation of hMSCs on the TCP-COL scaffold, and the BMP-7 (100) group had better effect than the BMP-7 (50) group (P0.05). However, it is noteworthy that in the BMP-7 (50) group and the BMP-7 (100) group, a significant up-regulation of COL1 gene was detected compared with the control group, indicating that when implanted for cartilage repair, BMP-7 might lead to bone formation. Conclusions BMP-7 could significantly induce the chondrogenic differentiation of hMSCs on the TCP-COL scaffold, however, the dose of BMP-7 must be carefully regulated for that BMP-7 might lead to bone formation. TCP-COL scaffolds are potentially usable for cartilage tissue engineering.