The Impact Of Adiponectin, And Osteocalcin For Bone Health After Ovariectomy

Objectives:The aim of this experimental study was to investigate the effect of ovariectomy on serum adiponectin, serum osteocalcin and bone mineral density in rats.Materials and methods:Forty five female Sprague Dawley rats were divided into three groups (n=15rats per group):sham-operated control, ovariectomized, and ovariectomized plus estrogen. After three months of experiment, rats were killed by decapitation after a12hour fast and the abdominal fat was separated, weighed and snap frozen in liquid nitrogen and stored at-80?until further analysis. Obtained serum from rats'blood sample was also kept at-80?. For all groups of rats, serum adiponectin and serum osteocalcin were measured by ELISA. Serum cholesterol, HDL cholesterol, and triglyceride levels were determined with Kit. The rats'left femoral bone mineral density was measured by DXA.Results:One week after surgery, a significant increase in body weight was found amongst ovariectomized rats and this significant increase persisted over the experiment period. After three months of experiment, significant increases were observed in serum adiponectin levels, in visceral fat and in serum osteocalcin levels in the ovariectomized rats. Alongside, decrease in distal BMD of the left femur was observed amongst ovariectomized rats when compared with control. The mean values of both serum osteocalcin and BMD between the ovariectomized rats and the control were statistically significant. However, the ovariectomized plus estrogen group showed significant decreases in body weight, in visceral fat, and in serum adiponectin but no significant changes were found in serum osteocalcin levels. Ovariectomy induces an increase in serum adiponectin levels, in serum osteocalcin levels, and in bone turnover in rats.Conclusion:We found that estrogen administration induces decreases in body weight, visceral fat and serum adiponectin levels of ovariectomized rats without any significant changes in both serum osteocalcin levels and BMD. Oestrogen-deficiency by ovariectomy induces an increase in bone turnover coinciding with higher levels of serum osteocalcin in the ovariectomized rats. Indeed, combination of serum osteocalcin and BMD may be a better predictor of the fracture risk.