[Effects of the stilbene extracts from Cajanus cajan L. on ovariectomy-induced bone loss in rats].

The Cajanus cajan L. is a natural plant, which contains lots of potential active components. The effects of the stilbene extracts from Cajanus cajan L. (sECC) on ovariectomy (OVX)-induced bone loss in rats were identified. All experimental female rats were divided into 6 groups, i. e. sham-operated rats, OVX rats, 17beta-estradiol (E2)-treated rats, sECC-treated rats with three dosages, 50, 100, and 200 mg x kg(-1), separately. Two weeks after the operation, different dosage of sECC, E2 or deionized water were given to the 6 groups of rats, respectively for another 8 weeks through stomach. Then, all rats were killed. The body weight and uterus wet weight were measured. Contents of serum E2, follicle stimulating hormone (FSH), and luteinizing hormone (LH) were measured by radioimmunoassay. Femoral morphology was observed by HE stain. The results showed that there were no changes of the uterine weight and serum E2 concentration in sECC-treated rats compared with OVX rats. However, the serum FSH and LH concentrations reduced by 11.5% and 15.2% (P < 0.05), respectively. By HE staining, it is found that the 60% of the femur structure had been significantly improved in OVX rats treated with 200 mg x kg(-1) of sECC. The trabeculae were thicker and larger than that of OVX rats. It is clear that sECC improved femoral morphological structure and decreased FSH and LH contents without affecting serum E2 level and uterine weight in OVX rats. The results suggested that sECC had potential action in treatment of postmenopausal osteoporosis.