Decrease in myocardial antioxidant capacity and cardiac function precedes oxidative stress-mediated lipid peroxidation damage in early stage diabetic rats

Abstract

Objective: To investigate the changes of myocardial antioxidant capacity and its relationship with cardiac function and reactive oxygen species mediated lipid peroxidation production in rats with early stage diabetes. Methods: Sixteen Wistar rats were randomly assigned to non-diabetic control group (n=8) and diabetic group. Diabetes were induced by a single intravenous injection of streptozotocin (60 mg/kg). Four weeks after the establishment of diabetes, cardiac function, myocardial antioxidant capacity and lipid peroxidation product 15-2t-Isoprostane as well as plasma total antioxidant concentration were assessed. Results: As compared to the control group, plasma and cardiac level of 15-F2t-Isoprostane did not increase in the 4 week diabetic rats. However, my-ocardial antioxidant capacity was decreased in the diabetic rats, which was reflected by the increased production of TBARS (thiobartituric acid reactive substances) when heart tissue was subjected to in vitro challenge to the oxidant t-butylhydroperoxide (P<0. 05), accompanied with reduced cardiac ejection fraction (P<0.05 vs control). Conclusion: Decrease in myocardial antioxidant capacity and cardiac function precedes oxidative stress-mediated lipid peroxidation damage in early stage diabetes in rats.