Effects of chronic ethanol exposure on acetaldehyde and free radical production by astrocytes in culture

Abstract 

In a previous study, the production of acetaldehyde and free radicals derived from ethanol was characterized in astrocytes in primary culture. In the present study, the effects of chronic exposure on the production of both compounds as well as on the main antioxidant system were compared with those of an acute exposure. This was done to better understand the different ways the brain reacts to these modes of exposure. Under these conditions, both a time-dependent increase in the accumulation of acetaldehyde and a decreased formation of the α-hydroxyethyl radical were shown. This was associated with increased activities of catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPX) and with decreased glutathione (GSH) content. These effects, which counteract reactive oxygen species (ROS) formation by stimulating the main enzymes of the antioxidant system, were also associated with the reduced amount of radicals derived from ethanol. This could be a beneficial effect, but this was counter-balanced by the increased rate of acetaldehyde accumulation, whose high toxicity is well known. All these effects underline the crucial role played by catalase which, on one hand converts hydrogen peroxide to water and, on the other hand, ethanol to acetaldehyde.