Effectiveness of Telmisartan as an Adjunct to Metformin in Treating Type II Diabetes Mellitus in Rats

The monitoring reports of most patients with type II diabetes mellitus (T2DM) revealed that monotherapy with metformin could not achieve long-term glycemic control. Thus, we designed this study aiming to investigate the effect of telmisartan, a unique AT1 receptor antagonist and a partial agonist of peroxisome-proliferator activated receptor gamma (PPARγ), individually and as an adjunct to metformin, on a rat model that simulates the metabolic characteristics of human T2DM. Adult male Wistar rats were fed high-fat, high-fructose diet (HFFD) for 8 weeks followed by a single low dose of streptozotocin (STZ) (35 mg/kg/day, i.p.) rendering them diabetic and insulin resistant. The effectiveness of both drugs and their combination was tested by assessing the changes in the levels of serum glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR) index, lipid profile and adiponectin. In addition, the level of reduced glutathione (GSH) in the liver, was investigated. Results showed that the addition of telmisartan to metformin successfully restored serum glucose back to normal levels and corrected the altered serum total cholesterol (TC), triglycerides (TG) and adiponectin, emphasizing the potential role of telmisartan as an adjunct to metformin.