| Objective To investigate the effect of GLP-1 analogue liraglutide on the serum levels of osteoprotegerin (OPG), receptor activator of nuclear factor-kappa B ligand (RANKL), and bone mineral density in diabetic rats. Methods Healthy male SD rats were randomly divided into normal control group (NC), diabetes mellitus (DM) group, low dose liraglutide group (LR-L), and high dose liraglutide group (LR-H). Type 2 diabetic rat model was induced with high fat and sugar diet combined with low-dose streptozotocin (STZ). Rats in LR-L group received 400 ug/kg/d of liraglutide with subcutaneous injection. Rats in LR-H group received 800 ug/kg/d of liraglutide subcutaneously. After 4 weeks, rats were sacrificed. The concentrations of blood glucose, serum calcium, phosphorus, alkaline phosphatase, total cholesterol, and triglyceride were measured. OPG and RANK were detected using ELISA method. Bone mineral density was detected with DEXA. Results Comparing with those in NC group, 1) The body weight reduced in DM, LR-L, and LR-H group. The body weight in LR-L and LR-H group was lighter than that in the DM group. It was not different between LR-L group and LR-H group. 2) Blood glucose increased in DM, LR-L, and LR-H group. Blood glucose in LR-L and LR-H group was lower than that in DM group. It was not different between LR-L and LR-H group. 3) The serum concentrations of OPG and RANKL increased significantly in DM, LR-H, and LR-L group, and the difference was statistically significant (P<0.05). The serum concentration of OPG in LR-L group is higher than that in DM group, and the difference was statistically significant (P<0.05). The serum concentration of OPG in LR-H group was higher than that in DM group, but the difference was not statistically significant. The serum concentration of RANK in LR-H and LR-L group was significantly lower than that in DM group. 4) The serum OPG/RANKL ratio in DM group was lower than that in NC group. It was higher in LR-L and LR-H group than that in DM group, and the difference was statistically significant (P<0.05). 5) The whole body BMD was lower in DM, LR-I, and LR-H group, and the difference was statistically significant (P<0.05). There was no significant difference among the 3 groups. Conclusion Liraglutide plays a role in reducing the body weight in type 2 diabetic rats, reducing the serum RANKL, and elevating serum OPG. However, bone mineral density does not increase after liraglutide treatment. |