Interaction of exercise training and chronic ethanol ingestion on hepatic and plasma antioxidant system in rat

This study was undertaken in order to investigate the interactive effects of exercise training and chronic ethanol consumption on the antioxidant system in rat liver and plasma. Fisher-344 rats were treated in separate groups as follows: sedentary control (SC); exercise training (ET) for 6.5 weeks; ethanol 20% (2.0 g kg-1, p.o.) for 6.5 weeks; and ET and ethanol administration. In liver, ET significantly decreased the malondialdehyde (MDA) level (73% of SC). Chronic ethanol significantly increased catalase (CAT) activity and MDA levels (126% and 135% of SC), respectively, and also depleted the reduced glutathione (GSH) level and the reduced to oxidized glutathione (GSH/GSSG) ratio (81% and 38% of SC), respectively. Exercise training plus ethanol significantly increased CAT and glutathione reductase (GR) activity (126% and 118% of SC), respectively, and decreased the MDA level (67% of SC). In plasma, ethanol significantly enhanced CAT activity and MDA levels (173% and 221% of SC), respectively. Ethanol ingestion also increased the CAT/superoxide dismutase (SOD) ratio (216% of SC) in plasma. Training plus ethanol ingestion significantly increased CAT activity and MDA levels (208% and 148% of SC), respectively, and increased CAT/SOD and glutathione peroxidase (GSH-Px)/SOD ratios (279% and 142% of SC), respectively. The data indicate that the combination of exercise and ethanol ingestion resulted in an enhanced hepatic CAT and GR activity to eliminate H2O2 and to maintain endogenous GSH levels. Thus, training ameliorated the ethanol-induced oxidative injury in the liver. The ratio of CAT/SOD in plasma increased twofold due to chronic ethanol intake and threefold due to the combination, which may be used as an index of oxidative stress.