Exercise modulates heat shock protein 27 activity in diabetic cardiomyopathy

AIMS:Heat shock protein 27 regulates homeostasis of skeletal and cardiac muscle proteins in various stressful states including diabetes and exercise. Aerobic exercise can inhibit or ameliorate cardiac structural abnormality and dysfunction in diabetic cardiomyopathy. The aim of this study was to evaluate the role of HSP27 in aerobic exercise improving cardiac diastolic dysfunction in type 2 diabetic rats. METHODS:Forty male Sprague-Dawley rats were randomly divided into the following groups: control, control + aerobic exercise, diabetic, and diabetic + aerobic exercise. Diabetes was induced by feeding with a high-fat high-sugar diet for 7-weeks followed by a single intraperitoneal injection of streptozotocin (30 mg/kg) in male rats. Moderate aerobic exercise training was performed on a treadmill for 8 weeks after induction of diabetes. KEY FINDINGS:Aerobic exercise increased left ventricular end-diastolic internal diameter, left ventricular end-diastolic volume, myocardial HSP27 protein expression, HSP27-S82 phosphorylation levels, pHSP27-titin binding and improved cardiac muscle fibre alignment in diabetic rats. SIGNIFICANCE:Our study indicates that moderate aerobic exercise increases HSP27 activation, improves cardiomyocyte fibre alignment and restores cardiac diastolic function.