Potential utility of sodium selenate as an adjunct to metformin in treating type II diabetes mellitus in rats: a perspective on protein tyrosine phosphatase.

Metformin is widely regarded as the standard first-line antidiabetic agent, in terms of efficacy and safety profiles. However, in most patients with type II diabetes mellitus (T2DM), it was found that metformin alone is not enough to adequately control hyperglycemia. Thus, we designed this study with the aim to investigate the effect of sodium selenate, a protein tyrosine phosphatase (PTP) inhibitor, individually and as an adjunct to metformin, on a rat model that simulates the metabolic characteristics of human T2DM. T2DM model was achieved by feeding the rats with high-fat, high-fructose diet (HFFD) for 8 weeks followed by a low dose of streptozotocin (STZ) (35 mg/kg/day, i.p.). Changes in serum glucose, insulin, adiponectin, homeostasis model assessment of insulin resistance (HOMA-IR) index, and the lipid profile were assessed. In addition, the level of reduced glutathione (GSH) and the activity of PTP were determined in the liver. Results showed that the addition of sodium selenate to metformin was able to restore hepatic GSH back to normal levels. Also, this combination therapy corrected the altered serum total cholesterol (TC), triglycerides (TG), and adiponectin levels. In conclusion, additive therapeutic effect was recorded when sodium selenate was used as an adjunct to metformin.