Abstract
Mesenchymal stem cells (MSCs) may be easily isolated from the bone marrow, and possess multi-lineage differentiation potential and various therapeutic applications. The differentiation of MSCs into osteoblasts is a complex process that is regulated by multiple internal and external factors. In the present study, the differentiation of MSCs isolated from rabbit bone marrow into osteoblasts using different osteoblast inductive media in the presence of dexamethasone, bone morphogenetic protein 2 (BMP-2), 1,25-dihydroxyvitamin D3, transforming growth factor β (TGFβ), platelet lysate and cyclooxygenase 2 (COX2), respectively. Alkaline phosphatase (ALP) activity, mineralization, collagen type (Ct) I and osteocalcin activities, and the mRNA and protein expression levels of vascular endothelial growth factor (VEGF), BMP-2 and Ct II were measured during the differentiation process in MSCs treated with different inducers. Rabbit MSCs were successfully isolated and were observed to be predominantly circular in shape after culture for 24 h. Following subculture for 5 days, the cells demonstrated a spindle shape. ALP, Ct I and osteocalcin activities were higher in cells cultured in dexamethasone, BMP-2 and TGFβ compared with the activities in control cells. Following differentiation, the dexamethasone, BMP-2 and TGFβ groups demonstrated significantly enhanced mineralization of MSCs detected by Alizarin Red S staining. The mRNA and protein expression levels of VEGF, BMP-2 and Ct II were significantly increased in the same groups compared with the levels in the control group. In conclusion, rabbit MSCs were successfully isolated from bone marrow and differentiated into osteoblasts indicated by raised ALP, Ct I and osteocalcin activities, mineralization and expression of osteogenesis-inducing genes and proteins. The present study revealed that dexamethasone, BMP-2 and TGFβ have a positive effect on cell differentiation.