Metformin improves the glucose and lipid metabolism via influencing the level of serum total bile acids in rats with streptozotocin-induced type 2 diabetes mellitus.

OBJECTIVE: To study the effects of metformin on streptozotocin-induced type 2 diabetes mellitus (T2DM) in rats.
MATERIALS AND METHODS: Wistar male rats were divided into two groups: standard diet (SD, n = 20) group and high-fat diet (HFD, n = 80) group. Twenty rats in HFD group were randomly treated with metformin (EI group). After 6 weeks, among rats in HFD group, 20 rats were intraperitoneally injected with citrate buffered saline (IR group), 20 rats treated with metformin per day for 4 weeks (LI group), and 20 rats were given nothing (DM group). Rats in SD group were injected with citrate buffered saline as normal control (NC) group. Moreover, streptozotocin (STZ) was used for inducing diabetes. The metabolic parameters, such as body weight, fasting blood glucose (FBG), fasting insulin concentration (FINS), total cholesterol (TC), total triglycerides (TG), low-density lipoprotein cholesterol (LDLC) and total bile acid (TBA) were measured.
RESULTS: Compared with SD group, the levels of body weight, FBG, TC, LDLC, TBA and FINS and AUC (glucose) were significantly higher in HFD group. After administration of metformin, the levels of FBG, TG, TC, LDLC and TBA in DM and LI group were higher than NC group. Besides, the FBG, TG, TC, TBA and LDLC levels in EI group were higher than DM group.
CONCLUSIONS: Metformin may help to improve the glucose and lipid metabolism by influencing the level of serum total bile acids. A combination of HFD and metformin could be effective in the treatment of rats with T2DM.