Influence of aerobic or resistance physical exercise on skeletal muscle of rats with myocardial infarction

Abstract

Oxidative stress and imbalance between anabolic and catabolic processes are involved in heart failure-associated skeletal muscle changes. Several positive effects from aerobic exercise have been described in heart failure. However, despite recent studies reporting beneficial effects from resistive exercise, the mechanisms involved in its effects are not completely clear. Resistive exercise increases muscle trophicity by activating satellite cells. We have not identified studies evaluating the effects of resistive exercise on skeletal muscle during cardiac remodeling and heart failure. The purpose of this study is to compare the effects of aerobic and resistive exercise started during compensated cardiac remodeling on phenotypical and molecular changes that occur during myocardial infarction (MI)-induced heart failure. Three months after inducing MI, Wistar rats will be assigned into four groups: Sham; sedentary MI; MI subjected to aerobic exercise; and MI subjected to resistive exercise. The rats will be trained three times a week for three months on a treadmill running or resistance exercise on stairs. Echocardiogram will be performed before and after training. The percentage of infarcted area and muscle throphicity will be determined by morphometric analysis. Protein expression of MAPKs, NF-kappaB, and ubiquitin-proteasome pathways, TNF-alfa and Pax-7 will be analyzed by Western-blot. Total ROS generation will be assessed by quantifying products derived from oxidation of dihidroetidio by HPLC. Determination of energy metabolism and the antioxidant enzymes catalase, superoxide dismutase, and glutathione peroxidase will be quantified by spectrophotometry; satellite cells activation will be evaluated by immunofluorescence for MyoD, NCAM, and neonatal isoform of myosin heavy chains. Serum concentration of TNF-alfa will be assessed by ELISA. Statistical analysis: ANOVA