[Effect of natural calcium against osteopenia in ovariectomized rats]

This study was designed to test the effect of natural calcium on the bone loss induced by ovariectomy in rats. Thirty female four-month rats were divided into three groups: sham operated group (Sham), ovariectomized group (OVX) and ovariectomized with calcium supplementation group (OVX + CA). OVX + CA rats were treated with calcium at a dose of 50 mg/kg weight per day for 90 days after surgery. Blood biochemical analysis, bone pathology, bone histomorphometric measurement and bone weight were processed. OVX rats were characterized by thinning, wormerosion like loss of trabecular bones, decreased volume of cancellous bone, increases in osteoblast index and osteoclast index, decreases in wet, dry and ash weights of left femur, and decreases in contents of calcium and phosphorus of bones. Treatment of OVX + p6 rats with calcium provided complete protection against bone loss and significantly depressed bone turnover. Our results indicate that natural calcium is effective in prevention of osteopenia in ovariectomized rats. The authors believe that the main mechanism of calcium against bone loss exists in correction of minus calcium balance, and depression of high bone turnover, especially the absorption action of osteoclasts.