Study On Effects Of Liraglutide On Bone Mineral Density And Bone Brittle Degree In Rats Of High-fat Diet Inducing Obesity And The Underlying Mechanism

Objective: To investigate the protective effects of Liraglutide on bone in obese rats and its underlying mechanism.Methods:1 Establishment of rats with simple obesity: 30 SD rats of 24 weeks were chosen,and randomly divided into normal diet group(ND group),high fat diet group(HFD group)and high fat diet + Liraglutide group(HFGD group),n=10.HFD group and HFGD group were fed with high fat diet for 8 weeks,and those obese rats whose weight was 20% higher than the average of normal diet group were chosen to build the model.2 Intervention of Liraglutide: After the success of building the model,group HFGD was treated with Liraglutide for 28 days,0.4mg/kg/d,while the remaining two groups were given physiological saline.3 At the end of the twelfth experimental week,body weight and visceral fat were measured of rats in each group(visceral fat were taken after the rats were executed),and then the ratioes of visceral fat to body weight were measured;Bone mineral density(BMD)of right femur were measured using bone densitometer;The levels of Ca and P in serum of rats were measured by automatic biochemical analyzer;Von Kossa staining was used to observe the morphology of left femur;Enzyme-linked immnosorbent assay was used to detect the value of BAP,OCN,IL-6 TNF-??OPG and RANKL in rat serum after drug intervention;Quantitative Real-time-PCR was used to detect the level of OPG and RANKL mRNA in rat femoral bone after drug intervention.Results:1 Compared with the ND group,the body weight and the ratio of visceral fat to body weight in HFD group were significantly higher(P<0.05);Theexpression of OCN,OPG and BMD in serum were significantly lower(P<0.05);The expression of RANKL mRNA was significantly higher(P<0.05)and the expression of OPG mRNA was significantly lower(P<0.05).The trabecular bone at the femoral epiphysis end was sparsely arranged and became thiner and fractured in histomorphology.2 After the intervention of Liraglutide for 28 days,compared with the HFD group,the body weight,the ratio of visceral fat to body weight,the expression of BAP,IL-6 and TNF-? and RANKL in serum in HFGD group were significantly lower(P<0.05);the expression of OCN,OPG and BMD in serum were significantly higher(P<0.05);The expression of RANKL mRNA was significantly lower(P<0.05)and the expression of OPG mRNA was significantly higher(P<0.05).The level of bone plate was clear and dense,the trabecular bone was arranged concinnously in a narrow space in HFGD group.Conclusion:1 Obesity can lead to the change of bone tissue and bone metabolism in rats.2 The Liraglutide plays an positive role in bone metabolism and osteopsathyrosis,and it mainly regulate bone formation markers and inhibit osteoclasts indicators to perform bone protection effect.