| Abstract: | Objective To observe the effect of phytoestrogen coumestrol on the function of osteoblast including ALP and osteocalcin type I collagen, OPG and RANKL. Methods Osteoblasts obtained from fetal mouse calvaria and were incubated with coumestrol (0, 10-9-10-5 M) or 17β-Estradiol (10-8 M) for 48 hours. Alkaline phosphatase (ALP) activity and type I collagen contents was measured by enzyme digestion. Osteocalcin production was measured by radioimmunity. OPG and RANKL mRNA level were detected by RT-PCR and OPG protein was determined by Western Blot. Results Treated with coumestrol for 48 hours, ALP activity and type I collagen contents was dose-dependently increased by all kinds concentration of coumestrol and reached peak at 10-6 M (P<0.05) and then decreased slightly when cotreated with 10-5 M coumestrol. Coumestrol increased osteocalcin expression slightly, but there were no significant differences among groups. Coumestrol increased OPG mRNA expression and protein production in dose-dependently manner (P<0.05) and slightly decreased RANKL mRNA expression. Conclusions Coumestrol has an enhancing effect on the proliferation and differentiation of osteoblasts, at least in part, by stimulating OPG/RANKL expression in osteoblasts. |
