Document Type: Research Articles
Department of Medicine – Discipline of Gastroenterology – Universidade Federal de São Paulo – Escola Paulista de Medicina, UNIFESP/EPM, SP, Brazil.
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.