Many diabetic patients suffer from cardiomyopathy, even in the absence of vascular disease. The aim of this study was to see if dietary antioxidant supplementation has an inhibitory effect on the progression of cardiac tissue damage in streptozotocin (STZ)-induced diabetic rats.

Sprague-Dawley male rats (n=60) were used as experimental animals; they were divided into the normal control group and the diabetic group. Eight weeks after STZ injection (65 mg/kg of body weight), the products of lipid peroxidation (malondialdehydes, MDA), and the antioxidant enzyme superoxide dismutase (SOD), and catalase activities were determined in the cardiac tissue homogenates. The cardiac tissues were studied by light microscopy (LM) and electron microscopy (EM), and the tissue lesions were graded by a semiquantitative score.

The histologic scores for perivascular fibrosis, interstitial fibrosis and myocardial necrosis according to LM were significantly lower in the combined vitamin C & E treated rats than in the diabetic control rats. The ultrastructural scores for the overall cardiac morphology, mitochondria and myofilaments, according to EM, were significantly lower in the vitamin E treated rats and the combined vitamin C & E treated rats than in the diabetic control rats, even though this was of less magnitude than that in the insulin-treated diabetic rats.

These results suggest that antioxidants such as vitamin C & E might have a beneficial effect on diabetes as an adjunct therapy against lipid peroxidation and diabetic cardiomyopathy, in addition to the effects of instituting strict measures for controlling the blood glucose.