Swimming training restores the cardiac microRNA‐1, and ‐214 levels and cardiac contractility in rat after myocardial infarction (LB43)

Abstract

Myocardial infarction (MI) is accompanied by cardiac hypertrophy and fibrosis related to ventricular compliance reduction. MicroRNAs (miRNAs) are noncoding single stranded RNA molecules that regulate gene expression. The miRNA‐1, which target NCX and ‐214, which target Serca2a are involved in cardiac contractily. This study assessed the effects of swimming training (ST) on the cardiac miRNAs‐1 and ‐214 levels and ventricular function after MI. Male Wistar rats (n=6/group) were randomized into four groups: Control (CO), Training (TR), Control Infarcted (CI) Training Infarcted (TI). ST consisted of 60 min/days/5 days/week/10 week with 3% body overload began four weeks after the MI. Echocardiography was performed before and after the ST. MiRNAs analysis was performed by real‐time PCR in the Remote Myocardium (RM). The VO2max increased 38%in the TR compared with CO group and increased 14% in the TI compared with CI group. TI group decreased 15% the E/A ratio compared with CI group, showing improved ventricular compliance. Also, ST restored the cardiac shortening fraction in the TI group compared with CO group. MiRNA‐1 and ‐214 expression, respectively, were decreased (52%) and increased (54%) in the CI compared to the CO . However, ST increased (49%) and decreased (29%), respectively, the MiRNA‐1 and ‐214 expression in the TI compared to the CO . In this way, NCX and Serca2a were respectively decreased (36%) and increased (48%) in the TI compared to the CI. These results show that ST restored cardiac miRNA‐1 and ‐214 expression, which can be associate to the improved ventricular function, suggesting a mechanism for its potential therapeutic application in heart diseases.Grant Funding Source: Foundation for Research Support of the State of São Paulo ‐ FAPESP