Oxygen free radical injury of myocardial mitochondria in the experimental type 2 diabetic rats

AIM: To study the mechanism of diabetic cardiomyopathy and abnormality of oxygen free radicals. METHODS: The contents of myocardial cytosolic cytochrome C, mitochondria cytochrome C, mitochondrial calcium, NO, MDA and the activity of SOD and NOS were determined in diabetic rats induced by STZ. The pathological changes were observed under transmission electron microscope. RESULTS: Compared to the normal and ganoderma group, the levels of mitochondrial NO, iNOS, MDA, calcium and plasma Cyt-C in rat myocardium were higher (P<0.05), while mitochondrial Cyt-C and SOD were lowered in model group (P<0.05). The bouncary indistinct, disorganization, a focal loss of muscular fibril, myocardium mitochondria swelling, pulmonary vascular endothelial cellular swelling and obstructed lumen of the capillary were also observed under transmission electronic microscope. CONCLUSION: The findings indicate that oxyradical and lipid peroxidation might be associated with the damage of myocardial mitochondria in NIDDM rats. Cyt-C and mitochondrial calcium is also involved in the process.