Coumestrol promotes proliferation and osteoblastic differentiation in rat bone marrow stromal cells

Although the effects of coumestrol on osteoblasts and osteoclasts can be summarized as increasing the bone density and preventing bone resorption, direct and detailed effects of coumestrol on bone marrow stromal cells remain obscure. In the present study, the effects of coumestrol on proliferation and osteoblastic differentiation of rat bone marrow stromal cells (BMSCs) have been investigated; the regulative effect of coumestrol on BMSCs and skeletal system has also been discussed. The results showed that treatment with coumestrol increased cellular activities (analyzed by MTT assay), alkaline phosphatase (ALP), type I collagen and osteocalcin (OCN) activity as well as the protein and gene expression of OPG, gene expression ratio of OPG/RANKL and gene expression of estrogen receptor alpha(ERalpha). These results demonstrate that phytoestrogen coumestrol has a direct enhancing effect on the proliferation and osteogenic differentiation of bone marrow stromal cells, which would lead to stimulation of bone formation, and it can also protect the whole skeletal system by regulating OPG/RANKL expression, and these effects may be mediated by ERalpha.