Effects of BMP-2 and FGF-2 on osteoblast differentiation of murine MSCs in vitro

Objective: To study the effects of BMP-2 and FGF-2 on osteoblast differentiation of murine MSCs in vitro.

Methods: The bone marrow cells were collected from 3-18 month old C57BL/6J mice (50 mice), and they were isolated, enriched and expanded using bone marrow adherent culture, and then purified by immunomagnetic microbeads. At last they were identified as mesenchymal stem cells (MSCs). After the MSCs were cultured adherently for 24 hours, 100 microg/L BMP-2 and 0.5 nmol/L FGF-2 were added into osteogenic media separately for 7, 14 and 21 days, alkaline phosphatase (ALP) staining, alkaline phosphatase activities, Vonkossa staining, and Alizarin red S staining were performed step by step. Osteoblast differentiation marker genes including Runx2/cbfa1, ALP, collagen-1, and osteocalcin were investigated by RT real time PCR.

Results: ALP activities, calcium deposition and the osteoblast differentiation marker genes of BMP-2 group were markedly higher than those of osteogenic group. The mRNA of Runx2/cbfa1, ALP, collagen-1, and osteocalcin of BMP-2 group was highly expressed than that of osteogenic group. It was the same with FGF-2 group, but less evident than BMP-2 group.

Conclusions: BMP-2 and FGF-2 can induce murine MSCs to differentiate into osteoblast at different degrees.