Role of Insulin on The Development of Renal Injury in Streptozotocin‐induced Diabetic Dahl Salt Sensitive Rats

Abstract

Background: Previous studies have suggested that insulin resistance and hyperinsulinemia increase oxidative stress which is implicated in the progression of diabetic nephropathy. The present studies were designed to investigate the role of insulin in the progression of diabetic renal injury.Methods: Dahl salt sensitive rats were administered either with streptozotocin (STZ, 65mg/kg intraperitoneally), control solution (CONT, intraperiotneally), or STZ with insulin (10U/kg/day, subcutaneous infusion) (STZ+INS). Urine was sampled every week in a metabolic cage for urinary protein (UP), TBARS and hydrogen peroxide as a marker of renal injury and oxidative stress. Mean arterial pressure was measured with telemetry method.Results: Urinary protein, TBARS and hydrogen peroxide excretion was significantly increased in STZ group compared to those of CONT group. Mean arterial blood pressure tend to reduce in STZ group but was not different from STZ+INS group. Urinary protein was further increased in STZ+INS group compared to those of STZ group.Conclusion: These results indicate that diabetic induction would induce renal injury in Dahl salt sensitive rats with enhanced oxidative stress. Hyperinsulinemia is involved in the progression of diabetic renal injury independent of its blood pressure.