Abstract
BackgroundImpaired cardiomyocyte contractility and calcium handling are hallmarks of left ventricular contractile dysfunction. Exercise training has been used as a remarkable strategy in the treatment of heart disease. The microRNA-1, which targets sodium/calcium exchanger 1 (NCX), and microRNA-214, which targets sarcoplasmic reticulum calcium ATPase-2a (Serca2a), are involved in cardiac function regulation. Thus, the aim of this study was to evaluate the effect of exercise training on cardiac microRNA-1 and −214 expression after myocardial infarction.MethodsWistar rats were randomized into four groups: sedentary sham (S-SHAM), sedentary infarction (S-INF), trained sham (T-SHAM), and trained infarction (T-INF). Exercise training consisted of 60 min/days, 5 days/week for 10 weeks with 3 % of body weight as overload beginning four weeks after myocardial infarction.ResultsMicroRNA-1 and −214 expressions were, respectively, decreased (52 %) and increased (54 %) in the S-INF compared to the S-SHAM, while exercise training normalized the expression of these microRNAs. The microRNA targets NCX and Serca-2a protein expression were, respectively, decreased (55 %) and increased (34 %) in the T-INF group compared to the S-INF group.ConclusionsThese results suggest that exercise training restores microRNA-1 and −214 expression levels and prevents change in both NCX and Serca-2a protein and gene expressions. Altogether, our data suggest a molecular mechanism to restore ventricular function after exercise training in myocardial infarction rats.
Highlights
Impaired cardiomyocyte contractility and calcium handling are hallmarks of left ventricular contractile dysfunction
Ecocardiography data showed that Exercise training (ET) restored cardiac function in myocardial infarction (MI) rats [17]
In the trained infarction (T-INF) (1.74 ± 0.1) group we found a decrease of 17 % in the diastolic function represented by E/A ratio compared with the sedentary infarction (S-INF) group (2.05 ± 0.1) [17]
Summary
Impaired cardiomyocyte contractility and calcium handling are hallmarks of left ventricular contractile dysfunction. The aim of this study was to evaluate the effect of exercise training on cardiac microRNA-1 and −214 expression after myocardial infarction. Exercise training (ET) is a well-known therapeutic strategy used in humans and animal models to overcome the cardiovascular deleterious effects after myocardial infarction (MI) [1, 2]. ET postMI has favorable effects on left ventricular (LV) remodeling while improving LV functional capacity, ejection fraction, and early LV diastolic filling [2, 3]. MiRNAs are small noncoding RNAs that regulate post-transcriptional mRNA expression mainly by binding to 3′-untranslated region (3′-UTR) of the complementary mRNA sequence, resulting in translational repression and gene silencing. The modulation of miRNA by ET and its association to LV remodeling has recently been reviewed by us and other researchers [15,16,17,18]
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