Co-administration of Lisinopril and Valsartan has a Renoprotective Effect in Streptozotocin-Induced Diabetic Rats

The co-existence of hypertension with diabetes mellitus (DM) is very common and the antihypertensive agents are used in order to stop the acceleration of both macrovascular and microvascular complications. The aim of this study is to investigate the renoprotective effects of Lisinopril (Lis), valsartan (Val) and their combination in diabetic rats. Animals were allocated into five groups: non-diabetic control group, diabetic control group, Lis-treated group, Val-treated group, and combined treatment-group. Diabetes was induced by a single i.p. injection of 50 mg/kg streptozotocin (STZ). Drug treatment started one week after confirmation of diabetes and lasted for three weeks. Systolic blood pressure (SBP), serum creatinine, serum potassium, serum renal nitric oxide (NO) and renal aldose reductase activity (renal-ARA) were measured in all groups. Renal histopathological examination was also carried out. In the diabetic control group SBP, serum creatinine, serum potassium level and renal-ARA were significantly elevated while NO was not affected. Treatment with either Lis or Val alone significantly lowered SBP and serum creatinine but failed to decrease the elevated serum potassium level as compared to diabetic untreated group. Co-administration of both Lis and Val normalized SBP, serum creatinine and markedly decreased the elevated potassium level. The elevated renal-ARA was not ameliorated by any of the treatment strategies. Histopathological study revealed better protection of the renal tissue by combined therapy than by either drug alone. It could be concluded that combination of both Lis and Val has better renoprotective effects than single treatment with either drug in diabetic rats.