Effect of epimedium-derived phytoestrogen on bone turnover and bone microarchitecture in OVX-induced osteoporotic rats.

To investigate the preventive effect of epimedium-derived phytoestrogen (PE) on osteoporosis induced by ovariectomy (OVX) in rats, 11-month-old female Wistar rats were randomly divided into Sham, OVX and PE groups. One week after OVX, daily oral administration of PE (0.4 g.kg(-1).day(-1)) started in PE group, and rats in Sham and OVX groups were given vehicle accordingly. The administrations lasted for 12 weeks. The biological markers including serum osteocalcin (OC) and urinary deoxypyridinoline (DPD) for bone turnover were evaluated at the end of the 12th week. On the 13th week, all the rats were sacrificed. The right proximal tibiae were removed, subjected to micro CT for determination of trabecular bone structure and then bone histomorphometry was performed to assess bone remodeling. The OVX rats were in a high bone turnover status as evidenced by increased bone formation markers and bone resorption markers. Treatment with PE could suppress the high bone turnover rate in OVX rats. Micro CT data revealed that PE treatment could ameliorate the deterioration of the micro-architecture of proximal tibiae induced by OVX, as demonstrated by greater bone volume, increased trabecular thickness and less trabecular separation in PE group in comparison with OVX group. The static and dynamic parameters of bone histomorphometry indicated that there were significant increases in bone formation variables and significant decreases in bone resorption variables between PE and OVX groups. The findings suggest that PE has a beneficial effect on trabecular bone in OVX rat model and this effect is possibly associated with stimulation of bone formation as well as inhibition of bone resorption.