[Effects of recombinant human bone morphogenetic protein 2 and osteogenic agents on proliferation and differentiation of rat mesenchymal stem cells].

OBJECTIVE: To investigate the effects of the recombinant human bone morphogenetic protein 2 (rhBMP-2) and/or the osteogenic agents on proliferation and expression of the osteoblast phenotype differentiation of the SD rat mesenchymal stem cells (MSCs). METHODS: The rat MSCs were cultured in vitro and were randomly divided into the experimental groups (Groups A-I) and the control group. In the experimental group, MSCs were induced by rhBMP-2 in different doses (10, 50, 100 and 200 microg/L) in Groups B-E, the osteogenic agent alone (Group A) and by the combined use of rhBMP-2 [in different doses (10,50, 100 and 200 microg/L)] and the osteogenic agent in Groups F-I. The MTT colorimetric assay was used to evaluate the proliferation, and the activities of alkaline phosphatase (ALP) and osteocalcin (OC) were observed at 3, 6, 9, 12 days, respectively. RESULTS: The inverted phase contrast microscopy showed that MSCs by primary culture for 12 hours were adhibited, with a fusiform shape at 48 hours. At 4 days they were polygonal or atractoid, and were spread gyrately or radiately at 6 days. At 10 days, they were spread at the bottom of the bottle. The statistical analysis showed that the expression of the osteoblast phenotype differentiation of MSCs could be induced in the experimental groups. The proliferation of MSCs could be enhanced in a dose-dependent manner in Groups B-E. The expression of the osteoblast phenotype differentiation, which was tested by the activities of ALP and OC, was significantly higher in Groups F-I than in Groups A-E. CONCLUSION: The combined use of rhBMP-2 and the osteogenic agents can enhance the MSC proliferation and induce an expression and maintenance of the osteoblast phenotype differentiation of the rat MSCs.