Effects of low dose 17β-estradiol on bone mineral density, body fat and serum lipids in ovariectomized rats

Objective To evaluate the effects of low dose 17β-estradiol on bone mineral density (BMD), body fat and serum lipids in ovariectomized (OVX) rats. Methods A total of 208 SD rats aged 10 months were randomly divided into control, ovariectomized (OVX), 17β-estrdiol treated (EST, 10 μg·kg -1·day -1) and sham-operated (SHAM) groups and sacrificed at 3, 6, 9, 12, 15, 18 and 21 weeks after operation. Whole body BMD, body weight, body fat content and percentage of body fat were measured by DXA and serum triglyceride, cholesteral, high density lipoprotein (HDL) and low density lipoprotein (LDL) were assayed before sacrifice. Results The body weight and LDL were increased at week 3 after OVX whole body BMD decreased at week 15, LDL increased at week 9 and 18, and serum triglyceride and cholesteral increased, HDL decreased, body fat content and percentage of body fat content increased at week 21. EST rats displayed higher whole body BMD, serum triglyceride and cholesteral than OVX rats did at week 6. Before week 9 total body weight was decreased in EST rats as compared with OVX rats. The EST rats showed higher HDL than both OVX and Sham rats after 9 weeks. Conclusion The early administration of 17β-estradiol contributes to the increase of BMD, serum triglyceride, cholesteral and HDL, as well as the inhibition of body fat increment in OVX rats.