INFLUÊNCIA DO TREINAMENTO FÍSICO INTERVALADO DE ALTA INTENSIDADE E DO JEJUM INTERMITENTE SOBRE A MATRIZ EXTRACELULAR NO MIOCÁRDIO DE RATOS SAUDÁVEIS

Abstract

Background: High-intensity interval training (HIIT) and intermittent fasting (IF) are interventions that influence the cardiac extracellular matrix (ECM). However, the effects of these interventions on cardiac ECM are not fully understood. Objectives: To analyze the influence of HIIT and IF on metalloproteinase 2 activity, quantify the interstitial collagen fraction and protein expression of type III collagen and TGF-β in the myocardium of healthy rats. Methods: Male Wistar rats (n=40) were allocated to four groups: Control (C) Intermittent Fasting (IF), High Intensity Interval Training (T) and High-Intensity Interval Training and Intermittent Fasting (T-IF). Groups C and T were treated with daily ad libitum feed, while the animals in groups IF and T-IF received ad libitum feed on alternate days. Groups T and T-IF were submitted to the HIIT protocol (5 times/week). After 12 weeks of the experimental protocol, the animals were euthanized. Cardiac morphology and the expression of proteins related to cardiac remodeling were analyzed. Results: TGF-β protein expression was higher in the T group than in C (C: 1.00±0.27; IF: 1.23±0.49; T: 1.38±0.58; T-IF: 1.04±0.23 au) p<0.05. The interstitial collagen fraction was higher in T than in C and lower in TIF than in T (C: 3.42±0.91; IF: 2.84±0.98; T: 4.48±1.30; T-IF: 3.29±1.03 %) p<0.05. Conclusion: HIIT modulates the TGF-β pathway and increases interstitial collagen in the myocardium, while IF attenuates these effects, providing a cardioprotective effect.