Ethanol metabolites may directly or indirectly induce oxidative stress as a result of disturbed balance between pro- and antioxidative processes. An indirect effect of ethanol on the generation of oxidative stress is associated with the attenuation of intracellular defensive enzymatic antioxidants, e.g. gluthatione peroxidase, catalase, superoxide dismutase as well as water- and/or fat-soluble low-molecular antioxidants (e.g., vitamin C, vitamin E, glutathione, selenium).
The aim of our study was to evaluate the effect of 48h preincubation of mouse embryo fibroblast-like cells (3T3-L1) with vitamin C (VC, 0.06 mM) and glutathione (GSH, 0.05 mM) on their viability after exposure for 4, 8, and 24 h to ethanol (0.3 mM). Additionally, the activity of glutathione peroxidase (GSH- Px) and thioredoxin reductase (TrxR) enzymes as well as the level of thiobarbituric acid reactive substances (TBARS) were assessed in the exposed cells.
In our study, vitamin C and glutathione had no significant effect on cytotoxicity of ethanol. We observed differences in GSH-Px and TrxR activity depending on the duration of exposure to ethanol. The highest GSH-Px activity in cell lysates was measured after 8 and 24h of incubation with ethanol and both antioxidants, or ethanol alone. The highest TrxR activity was observed after 4h of incubation in the presence of ethanol or GSH. There were no effects of VC and GSH on the activity of the antioxidant enzymes in comparison to cells not supplemented with VC and GSH. Similarly, we were unable to show any significant differences in levels of TBARS except incubation for 24h, when concentration of TBARS was highest in cells exposed to ethanol and simultaneously supplemented with the antioxidants.