Abstract: AIM: To study effects of resveratrol on osteoprotegerin(OPG) and receptor activator of NF-κB ligand(RANKL) expression in femur of ovariectomized rats. METHODS: 48 female SD rats(3 months old) were assigned into 6 groups randomly:sham-operated group(SHAM);ovariectomized group(OVX);17β-estradiol replacement therapy group (ERT, 0.1 mg·kg^-1 ·d^-1, sc);high-dose resveratrol-treate group (RH, 40 mg·kg^-1·d^-1, i.p.);middle-dose resveratrol-treated group (RM, 20 mg·kg^-1 ·d^-1, i.p.); low-dose resveratrol-treated group (RL, 10 mg·kg^-1 ·d^-1, i.p.).Except for SHAM group, rats in other groups were operated by bilateral ovariectomy. Administration started at the 8th day after operation and lasted 8 weeks.At the end of the 9th week after operation, all rats were sacrificed.The bone mineral density (BMD) and vitodynamics properties(including ELASTIC, M-STRESS, M-LORD and STIFFNESS) of femurs were measured.The expression of OPG and RANKL in femurs of rats were observed by immunohistochemical staining methods. RESULTS: Compared with OVX group, resveratrol treatment (40 mg·kg^-1 ·d^-1 and 20 mg·kg^-1 ·d^-1) increased expression of OPG in femurs while decreased expression of RANKL in ovariectmized rats.In RH, RM, and ERT group, BMD, ELASTIC, M-STRESS of femurs were higher than those of OVX group. CONCLUSION: Resveratrol increased expression of OPG in femur while decreased expression of RANKL in ovariectmized rats, which was probably one of mechanism that resveratrol improve osteoporosis.

Key words: resveratrol, osteoporosis, osteoprotegerin, receptor activator of NF-κB ligand;