[Effect of physiological dosage of estrogen on the prevention of bone loss in rats induced by ovariectomy].

The effect of small dosage of 17 beta-estradiol (E2) on bone metabolism, bone mineral density (BMD) and biomechanical properties of bone in ovariectomized rats were observed. Twenty-one rats were divided into three groups. They were sham-operated group (A), ovariectomized group (B), and ovariectomized and treated with 17 beta-estradiol group(C). Rats were sacrificed after 9 weeks of treatment. Serum alkaline phosphatase (ALP) and osteocalcin(OC) contents were significantly increased; bone mineral content (BMC) of right femur and the third lumbar body(L3) and the biomechanical properties of right femur were decreased in group B. Treatment with E2 can reverse the changes of BMD and BMC in ovariectomized rats. There was no significant improvement on biomechanical parameters in group C rats. It is concluded that physiological dosage of E2 may inhibit bone resorption and bone formation and increase bone mass, but it may not improve the strength of bone.