Affiliation:
1. Experimental and Molecular Cardiovascular Laboratory and Heart Failure and Cardiac Transplant Unit, Cardiology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
2. Postgraduate Program in Cardiology and Cardiovascular Science, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
Abstract
Exercise promotes physiological cardiac hypertrophy and activates the renin-angiotensin system (RAS), which plays an important role in cardiac physiology, both through the classical axis [angiotensin II type 1 receptor (AT1R) activated by angiotensin II (ANG II)] and the alternative axis [proto-oncogene Mas receptor (MASR) activated by angiotensin-(1–7)]. However, very intense exercise could have deleterious effects on the cardiovascular system. We aimed to analyze the cardiac hypertrophy phenotype and the classical and alternative RAS axes in the myocardium of mice submitted to swimming exercises of varying volume and intensity for the development of cardiac hypertrophy. Male Balb/c mice were divided into three groups, sedentary, swimming twice a day without overload (T2), and swimming three times a day with a 2% body weight overload (T3), totaling 6 wk of training. Both training groups developed similar cardiac hypertrophy, but only T3 mice improved their oxidative capacity. We observed that T2 had increased levels of MASR, which was followed by the activation of its main downstream protein AKT; meanwhile, AT1R and its main downstream protein ERK remained unchanged. Furthermore, no change was observed regarding the levels of angiotensin peptides, in either group. In addition, we observed no change in the ratio of expression of the myosin heavy chain β-isoform to that of the α-isoform. Fibrosis was not observed in any of the groups. In conclusion, our results suggest that increasing exercise volume and intensity did not induce a pathological hypertrophy phenotype, but instead improved the oxidative capacity, and this process might have the participation of the RAS alternative axis.
Funder
Ministry of Science, Technology and Innovation | Conselho Nacional de Desenvolvimento Científico e Tecnológico (National Council for Scientific and Technological Development)
Conselho de Aperfeiçoamento de Pessoal de Ensino Superior - CAPES
Fundo de Incentivo a Pesquisa e Eventos do Hospital de Clínicas de Porto Alegre
Publisher
American Physiological Society
Subject
Physiology (medical),Physiology
Cited by
14 articles.
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