OBJECTIVETo investigate the preventive effects and possible underlying mechanism of different extracts of Kanggushu () on osteoporosis in ovariectomized rats.

METHODSOne hundred and sixtyfive female SD rats were divided into 11 groups: control, sham, model, Xianling Gubao Capsule (), nilestriol, Kanggushu aqueous extract high-, medium-, and low-dose and suet extract high-, medium-, and low-dose groups. The osteoporosis model was made by ovariectomizing the rats. The latter 8 groups were administered intragastricly with Xianling Gubao Capsule, nilestriol, Kanggushu aqueous extract and suet extract for 12 weeks, respectively, while the other 3 groups were administered orally saline. The whole body bone mineral density, bone mineral content, organ coefficient of uterus, serum estradiol and alkaline phosphatase contents, blood calcium, phosphorus, interleukin 6 and bone Gla-protein levels after treatment were monitored. Additionally, three-point bending test of femur, HE staining, and scanning electron microscope were performed to explore the pharmacodynamics and underlying mechanisms.

RESULTSIn comparison with ovariectomized rats of model group, Kanggushu aqueous extract high-dose resulted in an increased bone mineral density, bone mineral content and organ coefficient of uterus, improved estradiol level, and improved maximum load and structural stiffness (P<0.05 or P<0.01). Two-dimensional and three-dimensional trabecular structure was also observed under HE staining and scanning electron microscopy, and the number and thickness of trabecular bone in Kanggushu aqueous extract high-dose group was significantly increased compared to the model group, while the lipid droplets in bone marrow cavity were significantly less. However, there were no significant differences in blood calcium, total serum alkaline phosphatase and bone Gla protein among different treatment groups. Overall, the osteoprotective effects of Kanggushu aqueous extract were comparable to those of nilestriol and were significantly more effective than those of Xianling Gubao Capsule.

CONCLUSIONThe preventive effects of Kanggushu aqueous extract might be partly due to the increased estradiol level, accelerated restoration of bone trabecular reticulate structure, and accordingly increased bone mineral density in osteoporosis rats.