Oxidative Stress In The Liver Of Exercised Rats Supplemented With Creatine

Abstract

PURPOSE: There is evidence that creatine may exert antioxidant activities. To verify this hypothesis, this study examines the effects of aerobic training and creatine supplementation on biomarkers of oxidative stress in the liver of rats. METHODS: Adults (90 day) male wistar rats were submitted to Maximal Lactate State (MLSS) test in order to identify the aerobic/anaerobic metabolic transition during treadmill running. Soon afterwards, the rats were divided into 4 groups: Trained Supplemented (TS), Trained (T), Sedentary Supplemented (SS) and Sedentary (S). Trained rats ran on a treadmill for 40 minutes/5 days a week, in the speed equivalent to individual MLSS during 8 weeks. Supplemented rats received creatine monohydrate 5 days a week at a dose 1,5 g/kg body weight, by gavage during 8 weeks. At the end, all rats were sacrificed for analysis of biomarkers of lipid peroxidation: amount of substances that react with thiobarbituric acid (TBARs) and of the antioxidant defense system: catalase activity (CAT) and superoxide dismutase activity (SOD) in liver. The statistical procedure consisted of two-way ANOVA. When necessary, the Bonferroni post hoc comparison test was used. In all cases, the statistical significance was set at P<0.05. RESULTS: The amount of TBARs (mmol MDA/mg protein) was higher in the Sedentary SS (12.11 + 4.59) and S (15.21 + 5.81) groups than in the trained groups (ST 8.20 + 3.2; T 7.89 + 3.1). CAT activity (umol/min.mg protein) was higher in the Sedentary SS (0.59 + 0.16), S (0.49 + 0.09) groups and Trained group T (0.46 + 0.14) than in the ST group (0.37 + 0.10). There were no significant differences between groups in relation to the SOD activity (U/mL) (ST 15.43 + 3.16; T 13.84 + 3.75; SS 12.92 + 2.77 e S 11.34 + 2.18). CONCLUSION: The results of this study suggest that physical activity decreases membrane lipid peroxidation in the liver of rats, independently of creatine supplementation. This adaptation was not associated with the components of the antioxidant system evaluated in the present study. Support by the Brazilian Foundations: CAPES, Fapesp and CNPq