3 Analysis of antioxidants. A) Activity of SOD; B) GSH-GPx and C) CAT. The results are expressed as the mean + S.E. of 10 animals per group. TCr Angiogenesis inhibitor = Trained Creatine; T = Trained; CCr = Control Creatine; C = Control not trained. * different C; † different CCr; ‡ different T/C. Concentration of reduced glutathione (GSH), oxidized glutathione (GSSG) and ratio between reduced glutathione and oxidized glutathione (GSH/GSSG) in liver Rat liver values for GSH, GSSG and GSH/GSSG ratio at the end of the experiment showed no differences between groups (Figure 4). Figure 4 Concentration of reduced glutathione, oxidized glutathione and ratio reduced glutathione/oxidized glutathione in the liver the animals at the end of the experiment. The results are expressed as the mean + S.E. of 10 animals per group. TCr = Trained Creatine; T = Trained; CCr = Control Creatine; C = Control not trained. Discussion In recent years the use of creatine supplementation (CrS) whith antioxidant function has increased. Several studies have confirmed these effects and pointed to creatine as a new alternative in the prevention of oxidative stress in which creatine appears to play a crucial role in reducing the toxic effects of endogenous production of reactive oxygen species (ROS) [5, 26–28]. The literature indicates that 2% CrS in animal feed JQEZ5 purchase is able to
trigger a significant increase in phosphocreatine (PCr) and creatine levels in rat tissues [29, 30]. Using this amount of creatine, McMillen et al.  observed a significant increase in the total creatine content of rat gastrocnemius muscle in two weeks of supplementation. In the present study, significant increase in the hepatic creatine concentrations were demonstrated in CCr and TCr rats compared to the non-supplemented control groups, which supports prior findings in the literature [30, 31]. After confirming that dietary supplementation increased creatine concentration in rat liver, this study aimed to evaluate the possible
antioxidant effects of CrS in vivo. The results demonstrate that Mannose-binding protein-associated serine protease creatine exerts indirect antioxidant activity in rat liver, i.e., creatine increased the activity of antioxidant enzymes GSH-GPx and CAT. However, CrS was not effective in normalizing the increased concentrations of H2O2 triggered by exercise. In addition, no significant differences were observed in the concentration of TBARS between groups. H2O2 plays an important role in homeostasis. It participates in cellular induction of gene expression, among which are those genes responsible for antioxidant enzyme synthesis [32–34]. In the present study, we demonstrated that exercise-trained rats (T and TCr) had higher concentrations of H2O2 than sedentary rats (C and CCr). These data reinforce the observations of several authors that indicate that creatine appears to exert selective antioxidant effects [26, 27]. Lawler et al.