Impacto do treinamento intervalado de alta intensidade sobre o estresse oxidativo do músculo esquelético de ratos espontaneamente hipertensos

Abstract

Sedentary lifestyle is a risk factor for the development and progression of several diseases, especially cardiovascular diseases, such as arterial hypertension (AH), which affect quality of life and functional capacity. Continuous elevation of blood pressure can progress to heart failure (HF), generating muscle manifestations, such as increased oxidative stress in skeletal muscles. The NADPH oxidase complex is one of the main sources of reactive oxygen species (ROS) and among its signaling pathways are Nf-Kb and Ik-B. Physical exercise is the best method of combat and among them the high intensity interval type (HIIT) exercises have been widely used in individuals with AH. This modality has the characteristic of optimizing time and thus promoting greater adherence, in addition, they are also superior to continuous aerobic exercises because they offer greater gains in cardiorespiratory fitness (maximum VO2). The influence of HIIT on the biochemical and molecular mechanisms in skeletal muscle has not yet been elucidated. As sedentary lifestyle generates complications, investigating these control strategies is essential. Therefore, the aim of the study was to evaluate the effect of HIIT on oxidative stress in the skeletal muscle of spontaneously hypertensive rats. The study was approved by the Ethics Committee on Animal Experiments (Protocol CEUA 1167-2016). Twenty-five 12-month-old rats were used, divided into: sedentary (SHR, n = 9), HIIT training (HIIT, n = 10) and Wistar Kyoto control (WKY, n = 6). The rats were familiarized with HIIT for a week for 10 minutes on the treadmill. An incremental effort test was carried out until exhaustion to graduate the exercise intensity in the fourth week of training. HIIT was performed five times a week for eight weeks. Systolic blood pressure (SBP) was measured and the maximum exercise test was performed before and after training. After the end of the experimental design, the anterior tibial muscle was used for the following analyzes: hydrophilic antioxidant capacity (CAH), lipid peroxidation (MDA), protein carbonylation, interleukin-6 quantification and tumor necrosis factor-alpha. Additionally, we carried out the evaluation of the expression levels of the genes encoding members of the NADPH oxidase complex (NOX2, NOX4, p22phox and p47phox) and of the Nf-Kb and Ik-B pathways by RT-qPCR. For comparison between groups and treatments, ANOVA One-Way was used followed by Tukey or Kruskal-Wallis and Dunn’s or Tukey-Kramer and orthogonal contrast test (p <0.05). We found an increase in interleukin-6 and tumor necrosis factor alpha in the HIIT vs. WKY (p <0.05) and alteration in the expression levels of the genes involved with the sources that generate ROS, evidenced by the decrease in NOX2 and Ik-B in the HIIT vs. WKY (p <0.05). It is concluded that HIIT produces superior beneficial effects, through the regulation of oxidative stress and members of the inflammatory cascade in the skeletal muscle, in spontaneously hypertensive rats when compared to healthy sedentary rats.