Treinamento intervalado de alta intensidade: papel na prevenção da doença hepática gordura não alcoólica em camundongos alimentados com dieta hiperlipidica

Abstract

Non-alcoholic fatty liver disease (NAFLD) attracts attention from the scientific community due to its silent harmful progression and non-existence of a specific treatment. Glucolipotoxicity triggers endoplasmic reticulum (ER) stress with decreased beta-oxidation and enhanced lipogenesis, favoring NAFLD onset. Regular physical exercise could prevent NAFLD by preserving ER and mitochondrial function. This study evaluated whether high-intensity interval training (HIIT) could prevent NAFLD development in HF-fed C57BL/6, focusing on ER homeostasis and mitochondrial function. Forty male C57BL/6 mice (3 months old) made up four experimental groups: control (C) diet group, C diet + HIIT (C-HIIT) group, high-fat (HF) diet group, and HF diet + HIIT (HF-HIIT) group. HIIT sessions lasted 12 minutes and were taken thrice weekly by trained mice. Diet and exercise protocols lasted for ten weeks. HIIT protocol prevented weight gain and maintained insulin sensitivity in the HF-trained group. A chronic HF diet increased ER stress-related genes and protein expression, but HIIT achieved ER homeostasis, preserved mitochondrial ultrastructure, and maximized beta-oxidation. The increased Sirt1/Pgc1a expression implies that HIIT enhanced mitochondrial biogenesis and adequate mitochondrial dynamics. High hepatic Fndc5/irisin complied with anti-lipogenic and anti-inflammatory effects observed in the HF-HIIT group, reinforcing the anti-steatotic effects of HIIT. This study shows reliable evidence that HIIT maintained insulin sensitivity, prevented ERE, and enhanced hepatic beta-oxidation, impeding NAFLD development in this mouse model even with high energy intake from saturated fatty acids.