[Strontium ranelate promotes osteogenic differentiation of rat bone marrow mesenchymal stem cells by increasing bone morphogenetic protein-7 expression].

OBJECTIVE: To explore the role of bone morphogenetic protein-7 (BMP-7) in strontium ranelate (Sr)-induced osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).
METHODS: BMSCs were isolated from 4-week-old rats and cultured in vitro. The third or fourth passages of BMSCs were examined using alkaline phosphatase kit for changes in ALP activity in response to treatment with different concentrations of Sr. Calcium nodules in the induced cells were detected using alizarin red staining, and the cellular BMP-7 expression was detected by Western blotting.
RESULTS: Within the concentration range of 0.1-3.0 mmol/L, Sr dose-dependently increased ALP activity in rat BMSCs. ALP activity reached the highest level after treatment with 3 mmol/L Sr, which also significantly promoted the formation of calcium nodules. Within the range of 0.1-3.0 mmol/L, Sr dose-dependently enhanced the expression of BMP-7, and its peak expression occurred following 3 mmol/L Sr treatment. Noggin (100 ng/ml), an inhibitor of BMP-7, obviously suppressed Sr-induced over-expression of BMP-7 and reduced ALP activity and calcium nodule formation in the BMSCs.
CONCLUSION: Sr promotes osteogenic differentiation of rat BMSCs by increasing the expression of BMP-7.