Effects of Dietary Conjugated Linoleic Acid (CLA)on Antioxidant System in the Liver of Chronically Ethanol -Treated Rats

ABSTRACT

The study was designed to observe antioxidant activities of conjugated linoleic acid (CLA )by determining antioxidant enzyme protein levels [cytochrome P4502 E1 (CYP2E1 ), Copper, Zinc-superoxide dismutase (CuZn-SOD ), glutathione peroxidase (GSH-Px ), glutathione S-transferase (GST )] by Western blot analysis and the levels of alpha -tocopherol and 2-thiobarbituric acid reactive substances (TBARS )in the liver of chronically ethanol-treated rats. Sixty Sprague Dawley male rats were divided into 3 groups (Control, EtOH, EtOH + CLA ). All rats were fed Lieber-DeCarli liquid diet for 4 weeks by pair-feeding against the EtOH group. The liquid diet was supplemented with 1.77g CLA mixture per kg diet in the EtOH + CLA group. Isocaloric maltose dextrin was added in replace of 50g ethanol (36%kcal )for the Control group. Ethanol ingestion significantly increased the levels of CYP2E1 protein and TBARS, but significantly reduced CuZn-SOD protein level and increased GST protein level. There was no significant effect on the level of GSH-Px protein and alpha-tocopherol in the liver by ethanol. CLA supplementation with ethanol significantly increased the levels of CuZn-SOD, GSH-Px and GST and also significantly attenuated TBARS level, whereas there was no signi-ficant effect on the levels of CYP2E1 protein and alpha-tocopherol by CLA. Overall, the CLA supplemented to ethanol could significantly increase the levels of CuZn-SOD, GSH-Px and GST proteins and reduce the level of TBARS in the liver of chronically ethanol-treated rats.