Background: The intestinal mucosa is commonly exposed to oxidant nutrients and carcinogens, which can lead to the generation of free radicals. The antioxidants present in the diet assume great importance as possible protective agents, reducing the oxidative damage. In this way, we evaluated the antioxidant action of grape juice on preneoplastic lesions induced by azoxymethane (AOM) in Wistar rats. Methods: The colorectal carcinogenesis was induced by two intraperitoneal injections of 15mg/kg of AOM in Wistar rats. The animals were divided in 7 groups and treated with 1 and 2% concentrations of grape juice before and after carcinogen administration. After euthanasia, the expression of antioxidant enzymes catalase (CAT), copper-zinc superoxide dismutase (Cu/Zn-SOD) and manganese superoxide dismutase (Mn-SOD) CAT, SOD1 and SOD2 were evaluated by immunohistochemistry. Results: AOM decreased the expression of CAT and Mn-SOD enzymes, but not for Cu/Zn-SOD. We observed an increase expression of CAT and Mn-SOD after grape juice administration in some concentrations according to the time of administration of the grape juice before the carcinogen or just after the carcinogen. Conclusion: Our results suggest an independent action of each enzyme and a possible antioxidant action of the grape juice components in the diet being able to balance the body to neutralize the superoxide radicals and not leave them in the cell-damaging form.
Keywords: Colorectal cancer; aberrant crypt foci; grape; antioxidants; free radicals.
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