Comparison of the metabolic and antioxidant effects of diltiazem and vitamin E on streptozotocin-diabetic rats.

In this study, solitary and combined effects of vitamin E and the calcium-channel blocker diltiazem were investigated in streptozotocin (STZ)-induced diabetic rats. Thirty male Wistar albino rats, weighing approximately 200 g were used. Diabetes mellitus was induced by a single intravenous injection of STZ at a dose of 65 mg/kg body weight. Five experimental groups were established as STZ-diabetic, STZ-diabetic + vitamin E, STZ-diabetic + diltiazem and STZ-diabetic + vitamin E + diltiazem. Vitamin E was injected intraperitoneally three times a week at a dose of 500 mg/kg body weight. Diltiazem was given orally every day at a dose of 25 mg/kg body weight. At the end of the study (10 weeks) blood glucose levels of diabetic rats, which had received vitamin E and diltiazem, had significantly decreased when compared with untreated diabetic rats (P < 0.02). Similarly, HbA1c levels had significantly decreased in diabetic rats which had received vitamin E (P < 0.05), diltiazem (P < 0.01) and vitamin E + diltiazem (P < 0.02) when compared with untreated diabetic rats. Liver glutathione levels of diabetic rats, which had received vitamin E (P < 0.01) and vitamin E + diltiazem (P < 0.05) had significantly increased when compared with untreated diabetic rats. Liver lipid peroxide levels had significantly decreased in diabetic rats, which had received vitamin E (P < 0.001) and diltiazem (P < 0.01). With respect to their metabolic and antioxidant effects, vitamin E proved superior to diltiazem.