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Abstract Antioxidative effects of selenium plus vitamin E (Se + vit. E) or zinc plus vitamin C (Zn + vit. C) on some biochemical parameters of antioxidants defense system in the blood, pancreas, liver and kidney of streptozotocin (STZ)-induced diabetic rats were assessed, in addition to their histopathologic effects on the fine structure of the pancreas and cortex of the kidney of diabetic rats. The selected parameters included oral glucose tolerance test (OGTT), insulin level and liver glycogen content, erylhrocyte superoxide dismutase (SOD), glutathione peroxidase (GPXJ and catalase (CAT), serum glutathione reductase (GR), liver glutathione (GSH) ieveE and Hpid peroxidation of pancreas, liver and kidney. Male albino rats were divided into four groups (1) control group, (2) diabetic control group injected with a single inlraperitoneal injection of STZ to induce diabetes (45 mg/kg b. wt); (3) diabetic treated group treated wilh oral administration of Se (20u.mol/kg b.wt/day) and vit. E in a dose of 30 mg/animal/day dissolved in distilled water and given by gastric tube daily for 4 and 6 weeks following the onset of diabetes, (4) diabetic treated group treated with oral administration of Zn in a dose of 50 mg/kg b.wt/day, while vit. C was used in a dose of 50 mg/animal/day and given by gastric tube for 4 and 6 weeks following the onset of diabetes. The administration of both combinations of antioxidants showed a high efficiency indicated by significant decrease of glucose, increase of insulin and liver glycogen levels, elevation of GSH levels, SOD, GPX, GR activity and decreased activity of CAT together with marked inhibition of lipid peroxidation indicated by significant depletion of thiobarbituric acid substance levels. Histopathological and ultrastructural results of the pancreas confirmed the efficiency of Se + vit. E or Zn + vit. C indicated by increase of p ceils number and p granules, while most organelles regained their normal appearance. In addition, zymogen granules number of acinar cells increased in number and appeared more electron dense. The kidney also showed marked reduction of basal lamina of the proximal tubules and filtration barrier of Ihe glomerulus as compared to diabetic control rats. The results confirmed that both these antioxidant combinations were effective in counteracting the diabetogenic effect of STZ and the ensuing oxidative stress and tissue damage. However, the supplementation of Se + vit. E is recommended over that of Zn + vit. C because it showed a greater ameliorative potential in some biochemical parameters and ultrastructural observations. |