DIETARY SUPPLEMENTATION OF GRAPE POLYPHENOLS AND CHRONIC ETHANOL ADMINISTRATION ON LDL OXIDATION AND PLATELET-FUNCTION IN RATS

Polyphenolic compounds have been implicated as the active ingredients for the cardiac protective effect in red wine. We tested the effects o f dietary supplementation of polyphenols from grape (GP) and chronic e thanol administration on low-density-lipoprotein (LDL) oxidation and p latelet function in rats. Four groups of young male Sprague-Dawley rat s were fed the following diets for 2 months: (I) a high fat Lieber-DeC arli liquid diet with an isocaloric amount of maltose, (II) with 5% et hanol (w/v), (III) with 5 mg/dL of GP, and (TV) ethanol plus GP. Plate let aggregation was induced by thrombin and phorbol myristate acetate (PMA) and LDL oxidation was induced by Cu2+. Chronic ethanol administr ation resulted in a significant increase in LDL oxidation and this eff ect was partially protected by supplementation with GP. Although plate let number was not affected by either ethanol or GP administration, pl atelet aggregation induced by thrombin was reduced in ethanol, GP and ethanol plus GP groups as compared to controls. On the other hand, pla telet aggregation induced by PMA was not altered in any groups, sugges ting that protein kinase C was not a causal factor for the reduction o f aggregatory response induced by thrombin. These results show similar effects of ethanol and GP on platelet aggregation but different effec ts on LDL oxidation. It can be concluded that dietary supplementation with GP may exert partial protection on oxidative insults such as thos e elicited by chronic ethanol ingestion.