Effect of vitamin E administration on metabolic defects in myocardium of rats with streptozotocin-induced diabetes

The effect of vitamin E administration (dose 1,500 mg/kg of diet) and of insulin-dependent diabetes (streptozotocin dose 45 mg/kg body weight, duration 8 weeks) on antioxidant status of myocardium and on some lipid parameters were studied in male Wistar rats fed semisynthetic diet containing 0.1% cholesterol. Diabetes caused reduction of vitamin E levels in serum and in myocardium. Administration of vitamin E had hypocholesterolaemic effect only in control animals and accumulation of lipids in myocardium was affected neither in control nor in diabetic rats. Diabetes increased lipid peroxidation (monitored by the level of malondialdehyde - MDA) and the activity of catalase (CAT) in rat myocardium. Vitamin E supplementation caused reduction of MDA levels. This intervention lowered the activities of glutathione-dependent enzymes and caused a significant elevation in superoxide dismutase (SOD) and CAT activities both in control and diabetic animals. The alterations in antioxidant enzyme activities indicate that the protective effect of vitamin E is manifested also through the modulation of the activities of antioxidant enzymes.