INFLUÊNCIA DA SUPLEMENTAÇÃO COM CREATINA SOBRE OS NÍVEIS MINERAIS ANTIOXIDANTES E MORFOLOGIA DO FÍGADO EM RATOS WISTAR SUBMETIDOS A EXERCÍCIO FÍSICO INTERVALADO

Abstract

Introduction: Creatine is one of the most widely used dietary supplements worldwide. High-intensity interval training (HIIT) has emerged as a simple and practical form of exercise, including for athletes, providing results as expressive as other classic modalities. In detriment to skeletal muscle, where HIIT and creatine supplementation are widely studied, the effect of these two factors on the liver and the possible causes of these effects are poorly understood. The aim of the study was to investigate the effects of the combination of creatine supplementation and high-intensity interval training (HIIT) on tissue and functional integrity in the liver of Wistar rats. Sample and Method: 48 male Wistar rats, 60 days old, divided into four groups: sedentary control (C), sedentary under creatine (Cr), trained control (HT) and trained under creatine (HTC). Animals in groups C and HT were fed daily with commercial rodent chow (Nuvilab®, Brazil), while animals in groups Cr and HTC were fed with chow supplemented with commercial creatine monohydrate at a dosage of 2% of daily intake. In addition, animals in HT and HTC underwent a HIIT protocol, in the form of treadmill running, with the training intensity being adjusted every week by means of an exercise stress test. The experiment lasted 12 weeks. After euthanasia, tissue analyses were performed (morphology and histopathology, inductively coupled plasma optical emission spectrometry (ICP-OES) for quantification of micronutrients and malondialdehyde (MDA), and serum (markers of liver function and damage: total proteins and albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), alkaline phosphatase, fasting blood glucose, total cholesterol, triglycerides, creatinine). The Shapiro-Wilk test was used to test for data normality. Two-way ANOVA was used to test for significant differences between groups, and when there was, the Tukey test was applied. The Kruskal-Wallis test was used when the data presented nonparametric distribution. When there was a difference, the Dunn test was used. Results: They are presented in the format of articles, one of which is a narrative review on “Exercise, mTOR activation, and potential impacts on the liver in rodents”, in which it was observed that there was no consensus on what the repercussions on the liver would be, due to the divergence of results between previous studies, and another original article addressing the issue of oxidative stress in rats subjected to HIIT and supplemented with 2% creatine. In this original article, an increase in MDA and a decrease in absolute levels of Selenium (Se) were found, as well as in the Cu/MDA, Mn/MDA, Zn/MDA and Se/MDA ratios in response to HIIT, confirming that there was greater hepatic lipoperoxidation, however, without causing tissue damage or alteration of liver function. Conclusion: The impacts on the liver resulting from the practice of physical training and the modulation of mTOR remain unclear, and further studies are needed. The HIIT protocol applied, as well as the 2% creatine supplementation used in the study, were beneficial in terms of improving physical performance and metabolism, in addition to not harming the tissue and/or functional integrity of the liver.