Creatine supplementation and oxidative stress in rat liver.

Amanda C Sponton,Roberto C Vieira Junior,Rodrigo A Dalia,Carla Ribeiro,Maria Alice R Mello,Michel B Araújo,Leandro P Moura,Marcelo C Junior

doi:10.1186/1550-2783-10-54

Abstract

BackgroundThe objective of this study was to determine the effects of creatine supplementation on liver biomarkers of oxidative stress in exercise-trained rats.MethodsForty 90-day-old adult male Wistar rats were assigned to four groups for the eight-week experiment. Control group (C) rats received a balanced control diet; creatine control group (CCr) rats received a balanced diet supplemented with 2% creatine; trained group (T) rats received a balanced diet and intense exercise training equivalent to the maximal lactate steady state phase; and supplemented-trained (TCr) rats were given a balanced diet supplemented with 2% creatine and subjected to intense exercise training equivalent to the maximal lactate steady state phase. At the end of the experimental period, concentrations of creatine, hydrogen peroxide (H2O2) and thiobarbituric acid reactive substances (TBARS) were measured as well as the enzyme activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-GPx) and catalase (CAT). Liver tissue levels of reduced glutathione (GSH), oxidized glutathione (GSSG) and the GSH/GSSG ratio were also determined.ResultsHepatic creatine levels were highest in the CCr and TCr groups with increased concentration of H2O2 observed in the T and TCr animal groups. SOD activity was decreased in the TCr group. GSH-GPx activity was increased in the T and TCr groups while CAT was elevated in the CCr and TCr groups. GSH, GGS and the GSH/GSSG ratio did not differ between all animal subsets.ConclusionsOur results demonstrate that creatine supplementation acts in an additive manner to physical training to raise antioxidant enzymes in rat liver. However, because markers of liver oxidative stress were unchanged, this finding may also indicate that training-induced oxidative stress cannot be ameliorated by creatine supplementation.

Highlights

The objective of this study was to determine the effects of creatine supplementation on liver biomarkers of oxidative stress in exercise-trained rats
Exercise training was performed and creatine supplementation given over eight weeks with animals allocated into four groups of ten animals in each group: control group (C), sedentary rats that received a balanced control diet; creatine control group (CCr), sedentary rats that received a balanced diet supplemented with 2% creatine; trained group (T), rats that were subjected to a training protocol and received a balanced diet; and supplemented trained group (TCr), rats that were subjected to a training protocol and received a balanced diet supplemented with 2% creatine
Concentration of hydrogen peroxide (H2O2) and thiobarbituric acid reactive substances (TBARS) in the liver Liver H2O2 levels obtained at the end of the experiment were significantly increased in the exercise-trained groups T and TCr in relation to control groups C and CCr (Figure 2A)

Summary

Introduction

The objective of this study was to determine the effects of creatine supplementation on liver biomarkers of oxidative stress in exercise-trained rats. Physical activity modifies the balance between oxidative stress and antioxidant defense mechanisms. For both athletes and fitness enthusiasts, the combination of regular physical activity and antioxidant supplementation may have important restorative effects on the body’s oxidationreduction or redox balance. The antioxidant effects of creatine may derive from different mechanisms of action such as the indirect mechanisms involved in cell membrane stabilization and improved cellular energy capacity [11] and from its direct antioxidant properties [5]. As creatine has not shown significant antioxidant activity against hydrogen peroxide (H2O2), these findings demonstrate creatine’s selective antioxidant capacity

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