Early exercise training attenuates left ventricular dysfunction, myocardial infarction area and molecular abnormalities in diabetic rats

Abstract

In this study we evaluated the effects of early exercise training (ET) on mortality rate, myocardial infarction (MI) area and VEGF gene levels, as well as on left ventricular (LV) function and calcium handling abnormalities in diabetic rats after MI. Male Wistar rats were divided in sedentary (S) and exercise training (ET) groups: control (C), MI+S (SI), MI+ET (TI), diabetes+MI+S (SDI) and diabetes+MI+ET (TDI). After 20 weeks of ET, MI size although similar at the beginning (~40±3%), was reduced at the end of the protocol in trained groups. MI size reduction was associated with increased mRNA VEGF levels in trained animals. Trained rats displayed higher cardiac output and ejection fraction (TI: 59±4 and TDI: 58±4% vs SI: 40±1 and SDI: 54±1%) when compared to sedentary ones. This improvement on LV function in trained animals was associated with increased expressions of SERCA2 (25%) and phospholamban phosphorilated at serine 16 (34%). In addition, survival rate was improved after ET period (TI: 87 vs SI: 41% and TDI: 75 vs SDI: 30%). These results showed that early ET intervention induced MI area reduction, LV function and survival improvement in trained animals. Moreover, the improvement of mRNA VEGF levels and Ca2+ handling proteins 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.CNPq