Early exercise training intervention reverses left ventricular dysfunction and calcium handling abnormalities after myocardial infarction in diabetic rats.

Abstract

Male Wistar rats were divided in sedentary (S) and exercise training (ET) groups: control (C), myocardial infarction (MI)+S (SI), MI+ET (TI), diabetes+MI+S (SDI) and diabetes+MI+ET (TDI). After 20 weeks of ET, left ventricular (LV) function was assessed and intracellular Ca2+ proteins were analyzed by Western blotting. MI size althought similar at the begining (~40±3%) was reduced at the end of the protocol in trained groups as well as LV end diastolic pressure (TI: 19±6% and 5±0.6mmHg; TDI: 21±4 % and 7±2 mmHg) when compared to sedentary groups (SI: 36±3% and 16±2mmHg; SDI: 38±4% and 12±3mmHg). Trained groups (TI: 59±4 and TDI: 58±4 %) showed higher ejection fraction when compared to sedentary ones (SI: 40±1 and SDI: 54±1%). Survival rate was improved in trained groups (TI: 87% vs SI: 41% and TDI: 75% vs SDI: 30%). TDI rats displayed increased expressions of SERCA2 (25%) and phospholamban phosphorilated at serine 16 (34%). These results showed that early ET intervention improves the LV function and survival in TI and TDI animals. Moreover, the improvement of Ca2+ handling proteins observed only in TDI rats gives support to consider ET as a coadjuvant therapy able to induce additional changes at myocardium molecular levels in diabetic subjects after an ischemic event.