Effect of Chronic Moderate Intensity Exercise on Ischemia - Reperfusion Injury in Diabetic Cardiomyopathy

Objectives: Diabetes is a common metabolic disorder characterized by hyperglycemia. In diabetics, the heart becomes more susceptible to ischemia/reperfusion (I/R) injury. The reason for this deterioration in the heart is oxidative stress increase due to diabetes. Exercise applied at appropriate intensity and frequency reduces oxidative stress and has a protective effect against I/R damage. In our study, the effects of chronic moderate exercise on I/R damage and oxidative stress in diabetes were investigated. Materials and Methods: Ten-week-old male Wistar albino rats were used in the study (n=36). Animals were randomly divided into four groups: Control (K), Exercise (EX), Diabetes (DM), Diabetes+Exercise (DM+EX). Type I diabetes was induced by injection of streptozotocin (50 mg/kg). The exercise capacity (MEC) was determined by applying the incremental load test. Animals exercised 45 minutes/day, 5 days/week, for 12 weeks, corresponding to 70% of their MEC. Hearts were removed and placed in the Langendorff apparatus and 30 minutes of global ischemia/120 minutes of reperfusion was applied. Left ventricular developmental pressure, heart rate, rate-pressure product parameters were measured. Total oxidant and antioxidant status, thiol disulfide levels were measured in the plasma and left ventricular samples. Results: According to heart weight/body weight data, diabetes-induced hypertrophy developed in diabetic animals, and exercise could not prevent hypertrophy. The recovery after ischemia was impaired in the DM group, while it was increasing in the EX group compared to the K. A significantly worse recovery response was observed in the DM+EX group compared to the K and DM. No significant changes were found in the oxidative stress data both in the plasma and left ventricle samples. Conclusion: Current exercise protocol increased diabetes-induced I/R sensitivity. While there was a cardioprotective effect in EX, the protocol was not a suitable protocol for diabetics. No significant change in oxidative stress was observed. In future studies, valuable results can be obtained by enlarging the sample size and prefering lower exercise intensity.