The Effect of High Dietary Salt Consumption on Renal Function in Streptozotocin-Induced Diabetic Male Wistar Rats

Salt consumption has been linked to increased risk of development of type 2 diabetes mellitus and hypertension due to its glucose resistance and body weight promoting effects. This study investigated the effect of high dietary salt intake on renal function in diabetic male Wistar rats. Animals were divided into 4 groups (n=7). Group 1 (control group) were fed with normal rat chow, group 2 (Diabetic) were received streptozotocin (STZ, 60 mg/kg), group 3 (high Salt) were given 8% salt diet, and group 4 had both STZ (60 mg/kg) and feeding with 8% salt diet. Fasting blood glucose was measured weekly and after 28 days priorto sacrifice, blood pressure measurements and 24 h urine samples were collected. After sacrifice, blood was collected and serum was separated for biochemical analysis. The kidneys were removed and preserved in 10% formalin for histological examination. Serum urea, creatinine and urine urea increased significantly (p <0.05) across group, when compared with control, while urine creatinine reduced (p <0.05) in all groups. There was a significant (p <0.05) increase in superoxide dismutase and catalase in high salt and salt/diabetes groups, when compared with diabetic group. Glutathione peroxidase significantly increased (p <0.05) across groups. Histologically, kidneys showed signsof inflammation in diabetic group, hemorrhagic lesions in high salt group and both hemorrhagic lesions and inflammation in salt/diabetes group. High dietary salt consumption was shown to affect tubular and glomerular functions by altering kidney histoarchitecture and antioxidant defense system.