Exercise training restores the myogenic response in skeletal muscle resistance arteries and corrects peripheral edema in rats with heart failure

Abstract

Impairment of the myogenic response can affect capillary hydrostatic pressure and contribute to peripheral edema and exercise intolerance, which arc markers of heart failure (1IF). The aim of this study was to assess the effects of exercise training (ET) on myogenic response in skeletal muscle resistance arteries and peripheral edema in HF rats, focusing on the potential signaling pathways involved in these adjustments. Male Wistar rats were submitted to either coronary artery occlusion or a sham-operated surgery. After 4 wk. an exercise test was performed, and the rats were divided into the following groups: untrained normal control (UNC) and untrained HF (UHF) and exercise- trained (on treadmill, 50-60% of maximal capacity) NC (TNC) and exercise-trained HF (THF). Caudal tibial artery (CTA) myogenic response was impaired in UHF compared with UNC, and ET restored this response in THE to NC levels and increased it in 'TNC. Rho kinase (ROCK) inhibitor abolished CTA myogenic response in the untrained and blunted it in exercise-trained groups. CTA-stored calcium (Ca2+) mobilization was higher in exercise-trained rats compared with untrained rats. The paw volume was higher in UHF rats, and ET decreased this response compared with UNC. Myogenic constriction was positively correlated with maximal running distance and negatively correlated with paw volume. The results demonstrate, for the first time, that HF impairs the myogenic response in skeletal muscle arteries, which contributes to peripheral edema in this syndrome. ET restores the myogenic response in skeletal muscle arteries improving Ca2+ sensitization and handling. Additionally, this paradigm also improves peripheral edema and exercise intolerance. NEW & NOTEWORTHY The novel and main finding of the present study is that moderate intensity exercise training restores the impaired myogenic response of skeletal muscle resistance arteries, exercise intolerance and peripheral edema in rats with heart failure. These results also show for the first time to our knowledge that exercise training improving calcium sensitization through the ROCK pathway and enhancing intracellular calcium handling could contribute to restoration of flow autoregulation to skeletal muscle in heart failure.