Lipid peroxidation in vitamin E-deficient rats submitted to subtotal nephrectomy

Clinical and experimental evidence has indicated that chronic renal failure (CRF) is related to increased free radical production. CRF patients show increased lipid peroxidation after a progressive reduction in vitamin E, one of the most important antioxidants. In the present study the role of vitamin E deficiency in lipid peroxidation was investigated in rats submitted to subtotal nephrectomy. Male Wistar rats were divided into groups receiving different diets for a period of 45 days: SND - sham rats submitted to a regular diet containing vitamin E; ERD - nephrectomized rats submitted to a regular diet containing vitamin E; SDD - sham rats submitted to a vitamin E-deficient diet; EDD - nephrectomized rats submitted to a vitamin E-deficient diet. After 30 days the Experimental animals were submitted to 5/6 nephrectomy and the Controls were submitted to sham operation. The vitamin E levels of the SDD and EDD groups were significantly reduced (p < 0.05) in plasma (4.92 +/- 1.22 and 8.37 +/- 2.09 mmol/L, respectively), liver (7.57 +/- 2.72 and 9.44 +/- 2.55 mg/g tissue, respectively) and kidney (8.17 +/- 2.38 and 9.40 +/- 3.10 mg/g tissue, respectively) when compared to the SRD and ERD groups. In contrast, in the EDD group the levels of thiobarbituric acid-reactive substances, expressed as nmol/mg protein, were significantly increased (p < 0.05) in the liver (1.41 +/- 0.27) and kidney (1.67 +/- 0.47), and superoxide dismutase activity was significantly increased in the erythrocytes (4455.80 +/- 1322.63 Ug/Hb) compared to all other groups. The vitamin E-deficient diet associated with subtotal nephrectomy determined an increase in lipid peroxidation, suggesting an important role of free radicals in the development of chronic renal failure.