Rat kidney antioxidant response to long-term exposure to flavonol rich red wine

This study evaluated the antioxidant defense system of the rat kidney following chronic exposure to red wine rich in flavonols. Both ethanol and antioxidant non-alcoholic wine components, mainly polyphenols, could contribute to the antioxidant status of kidney. Adult rats were given separately, water, ethanol (12.5%), red wine or alcohol-free red wine. After ten weeks of treatment, blood samples were obtained to determine plasma antioxidant capacity (FRAP, ferric reducing ability of plasma), uric acid and ethanol levels. Kidney tissues (cortex and papilla) were separated to perform measurements of reduced glutathione (GSH), glutathione disulfide (GSSG), lipid peroxidation (malondialdehyde, MDA) and the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The activity of (Na + K)-ATPase, a membrane-bound enzyme, was also assessed. Red wine in plasma, elevated the FRAP without changing the concentration of uric acid; in kidney, it diminished the MDA production and elevated the GSH/GSSG ratio and the activity of CAT and GSH-Px. The activity of SOD did not change. Despite the finding that renal (Na + K)-ATPase activity was upregulated by ethanol, it was not altered by either red wine or alcohol-free red wine. The effects on the antioxidant enzymes could be attributed to ethanol, but the increase in the FRAP and GSH/GSSG ratio is attributed to the non-alcoholic components of red wine. These data suggest that there is an enhancement of the antioxidant defense potential in kidney and plasma, after chronic red wine consumption. Both ethanol and the non-alcoholic antioxidant constituents of red wine could be responsible for these effects. (C) 2002 Elsevier Science Inc. All rights reserved.