Vitamin E reduces glomerulosclerosis, restores renal neuronal NOS, and suppresses oxidative stress in the 5/6 nephrectomized rat

Chronic kidney disease is accompanied by nitric oxide (NO) deficiency and oxidative stress, which contribute to progression. We investigated whether the antioxidant vitamin E could preserve renal function and NO bioavailability and reduce oxidative stress in the 5/6th nephrectomy (NX) rat model. We studied the following three groups of male Sprague-Dawley rats: sham (n = 6), 5/6 NX control (n = 6), and 5/6 NX treated with vitamin E (5,000 IU/kg chow; n = 5). The 5/6 NX group showed increased severity of glomerulosclerosis vs. sham, and this was ameliorated by vitamin E therapy. Both 5/6 NX groups showed similar elevations in plasma creatinine and proteinuria and decreased 24-h creatinine clearance compared with sham. There was increased NADPH-dependent superoxide production in 5/6 NX rats vs. sham that was prevented by vitamin E. Total NO production was similarly reduced in both 5/6 NX groups. There was unchanged abundance of endothelial nitric oxide synthesis (NOS) in renal cortex and medulla and neuronal (n) NOS in medulla. However, in kidney cortex, 5/6 NX rats had lower nNOS abundance than sham, which was restored by vitamin E. An increased plasma asymmetric dimethylarginine occurred with 5/6 NX associated with decreased renal dimethylarginine dimethylaminohydrolase activity and increased type 1 protein arginine methyltransferase expression.