Histomorphometric study of the effect of nylestriol on bone turnover in ovariectomized rabbits

OBJECTIVE: To assess the effect of Nylestriol on postmenopausal osteoporosis in an attempt to reveal its mechanism. METHODS: Thirty-seven month-old female New Zealand white rabbits were randomized into 3 groups (10 rabbits per group): treatment group [ovariectomized (OVX) + nylestriol (2 mg, monthly)], OVX control group (OVX + vehicle) and normal control group (sham operation + vehicle). Six months later, all rabbits were subjected to tetracycline labelling and then were killed. Under VIDAS system, bone turnover was assessed by bone histomorphometry. RESULTS: Bone volume trabecular (BV/TV), relative osteoid volume (OV/BV), osteoblastic index (OBI) and bone formation rate at tissue level [BFR(T)] increased in treatment group compared with OVX control group and (or) sham control group. CONCLUSIONS: Nylestriol can increase the number of osteoblast, which resulted in more bone matrix production and consequently converted the bone turnover of OVX rabbits to a positive balance situation. It indicated that Nylestriol was probably a stimulator for osteoblast recruitment and (or) proliferation.