Prevention And Treatment Of Osthol On Osteoporosis In Ovariectomized Rats

Objective: To observe the effects of osthol on osteoporosis in ovariectomized rats, and explore its mechanisms.Methods: (l)Preventive experiment: sixty female SD rats were randomly assigned to six groups(n=10): sham operation group, osteoporotic model group, osthol 5mg/(kg·d) group, 10mg/(kg·d) group, 20mg/(kg·d) group, and nilestriol lmg/(kg·w) group. These experimental rats with the exception of sham operation group were ovariectomized and then administrated with osthol or nilestriol for 12 weeks. The rats were then killed and blood was taken for measurement of serum E2, Ca²+, P, ALP, BGP, CT and TGF- β₁. Bone mineral density(BMD), body weight, uterus weight, the number of endometrial gland, pathomorphism of femur and uteous, bone biomechanical properties were observed as well. (2) Remedial experiment: The method was the same as preventive experiment, but the rats were administrated after 12 weeks of the ovariectomized operation.Results: At 12 weeks after ovariectomy, serum E₂, Ca²+, CT, TGF-β₁ levels and BMD in osteoporotic model group were decreased, and serum levels of P, ALP, BGP were increased, femur trabecular bone was narrow, medullary cavity was bigger, endometrial epithelial cell was atrophied, myometrium was thin. These results suggested osteoporosis was generated. After treated with osthol, serum E₂, Ca²+, BGP, CT, TGF-β₁ levels and BMD were increased, while the activity of ALP was kept in high level, the trabecular bone was more widened and less broken, medullary cavity became smaller, the biomechanical properties of bone such as maximal bending load, bending moment, bending strength, coefficient of rigidity were significantly increased. Differences in body weight, the weight and pathomorphism of uterous were not found as compared withosteoporotic model group.Conclusion: Osthol could prevent and treat osteoporosis in ovariectomized rats, its mechanisms might be associated with the direct effect on estrogen receptor on osteoclast and osteoblast, increasing the levels of serum E2, BGP, CT, TGF- P 1, stimulating bone formation and restraining bone resorption. In addition, there was no effect on uteous in osthol-treated rats, which suggested that osthol might be selective estrogen receptor modulator.