Experimental Study of the Estrogen and Vitamin K on Osteoporosis of Ovariectomized Female Rats.

Abstract

Objective To find a group of simply, effective and cheap method to prevent and remedy osteoporosis(OP) in order to provide the evidence for developing medicines against osteoporosis. Methods Fifty Sprague-Dawley rats were taken as the osteoporosis model of the early menopause. They were randomly divided into 5 groups: ovariectomized group (OVX group, n=10), ovariectomize and estrogen treatment group (OVX+ E group, n=10), ovariectomized and vitamin K treatment group (OVX+ vit K group, n=10), ovariectomized and estrogen treatment and vitamin K treatment group (OVX+ E+ vit K group, n=10), and sham operation group (sham group, n=10). These rats were given different medicine according to their groups after a month of ovariectomized operation, then killed together 8 weeks later. The bone mineral density (BMD) of the left femur and morphological observation of bone trabecula for right femur were observed. The content of interleukin-6 (IL-6), bone gla protein (BGP) and insulin-like growth factor-1 (IGF-1) of blood serum from the right part heart were tested. Results ① Compared with OVX group and sham group, the content of bone mineral density and insulin-like growth factor-1 descend eminently, and the content of interleukin-6 and bone gla protein increased outstandingly. ② The pathological section of bone tissue of OVX group had a significant different compared with sham group, OVX+ vit K group, OVX+ E group, and OVX+ E+ vit K group under the forty times light microscopy. The form of bone tissue of OVX+ E+ vit K group was similar to that of sham group. ③Compared between OVX+ E group and OVX group, the bone mineral density in the femur shaft (loose bone) went up obviously, but the bone mineral density in the middle part of femur(dense bone) went up moderately, which had no statistical difference. The bone mineral density of the middle part of femur(dense bone) increased obviously with no difference with the growth of bone mineral density in femur shaft(loose bone) between OVX+ vit K group and OVX group. The bone mineral density in the middle part of femur and femur shaft rised dramatically than that of OVX+ E+ vit K group, which was closed to that of sham group. ④The content of interleukin-6 and bone gla protein of OVX+ E group was lower than that of OVX group with a significant difference. The content of insulin-like growth factor-1, bone gla protein of OVX+ vit K group went up and interleukin-6 went down compared with OVX group. The content of interleukin-6, bone gla protein and insulin-like growth factor-1 in OVX+ E+ vit K group was closest to that of sham group. Conclusion ①The decrease of contents of bone mineral density and insulin-like growth factor-1 and increase of interleukin-6 and bone gla protein in SD rats indicate that bone metabolism at the early menopause is in a state of high conversion and the reduce of estrogen makes a great contribution to the disease of osteoporosis. ② The decrease of estrogen level plays an important role in the process of osteoporosis. Vitamin K and estrogen have effective precaution against osteoporosis. The combination of estrogen and vitamin K are superior to using estrogen or vitamin K only. Key words: osteoporosis; vitamin K; estrogen(E2), interleukin-6; bone gla protein (BGP); insulin-like growth factor-1; bone mineral density(BMD)