Preventive effects of Polygonum orientale L. on ovariectomy-induced osteoporosis in rats.

Objective: The aim of the present study was to evaluate the effects of ethyl acetate extract of Polygonum orientale L. (POE) on ameliorating postmenopausal osteoporosis in ovariectomized (OVX) rats.Methods: Six-month-old female rats were randomly divided into seven groups: sham-operated; OVX; OVX with estradiol valerate; OVX with alendronate; and OVX with POE in graded doses (3.75, 5.0, or 7.5 g/kg/day). Administration began at week 6 after ovariectomy for 12 weeks. A comprehensive assessment of bone quality was performed, including serum biochemical markers, serum inflammatory factors, bone oxidative stress markers, bone mechanics, and bone histomorphometry.Results: POE treatment significantly decelerated OVX-induced body weight gain without affecting the uterus index and produced a significant decrease in the levels of serum bone turnover markers (p < 0.05 or p < 0.01). Biomechanical testing demonstrated that POE (5.0 and 7.5 g/kg/day) treatments significantly prevented the reduction in maximum stress and Young's modulus in OVX rats (p < 0.05). Compared with the OVX group, POE (3.75, 5.0, or 7.5 g/kg/day) treatments significantly increased trabecular bone mineral density by 35.03, 38.42, and 42.02%, respectively.Conclusion: Our findings suggest that POE has potential effects in regulation of bone metabolism and prevention of bone loss in postmenopausal osteoporosis.