RESUMO
The aim of the study was to assess the protective effect of (-)-epigallocatechin gallate (EGCG), a flavonoid abundant in green tea, against ammonium metavanadate (AMV)-induced oxidative stress in male Wistar rats. Four groups of animals have been used, a control group and three test groups. In the first test group, AMV was intra-peritoneally (i.p) injected daily (5 mg/kg body weight for five consecutive days). The second test group of animals was also injected daily with EGCG (5 mg/kg body weight) during the same period. However, the third test group was i.p. injected with both AMV and EGCG (5 mg/kg body weight for five consecutive days). When given alone, AMV induced an oxidative stress evidenced by an increase of lipid peroxidation levels (expressed as TBARS concentration) in kidney. In these animals, activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) were significantly decreased, suggesting significant reduction of the antioxidant defense system at the cell level. Kidney histological sections, showed glomerular hypertrophy and tubular dilatation. In AMV-treated animals receiving EGCG, the oxidative stress was much less pronounced and activities of antioxidant enzymes were kept close to control values. Histopathological changes were less prominent. Our results confirm that green tea and other sources of flavonoids might confer a strong protection against ammonium metavanadate-induced oxidative stress.