Ethanol and food deprivation induced enhancement of hepatotoxicity in rats given carbon tetrachloride at low concentration.

Effects of chronic ethanol consumption and one day food deprivation on the hepatotoxicity of low dose carbon tetrachloride (CCl4; 0 to 100 ppm inhalation for eight hours) in rats were investigated by using biochemical and histopathological methods. Liver malondialdehyde (MDA) contents were significantly increased by exposure to 5 ppm to 50 ppm CCl4 in ethanol treated rats or by exposure to 25 ppm to 50 ppm CCl4 in food deprived rats but not in rats without ethanol or food deprivation. The MDA concentrations reached a maximum at 10 ppm and 50 ppm CCl4 in ethanol treated and food deprived rats, respectively, and decreased to the non-exposed concentration at 100 ppm CCl4. At greater than or equal to 50 ppm CCl4 plasma MDA contents increased significantly only in ethanol treated rats. None of the exposure concentrations influenced plasma glutamic-oxaloacetic transamidase (GOT) and glutamic-pyruvic transaminase (GPT) activities in rats that were only exposed to CCl4 whereas exposure to 10 ppm or higher concentrations combined with ethanol increased both activities. To a lesser extent food deprivation combined with exposure to greater than or equal to 25 ppm CCl4 had the same effect. No histopathological changes were found in the liver of rats exposed to less than or equal to 10 ppm CCl4, and only a few ballooned hepatocytes were seen in centrilobular areas when exposure was 25 ppm or higher. The presence of ballooned and hepatocytes became a regular feature of mid-zonal areas in ethanol treated rats and in the centrilobular areas of food deprived rats after exposure to </= 10 and </=25 ppm CC1(4) respectively. Necrotic hepatocytes were seen in centrilobular areas in liver from ethanol treated and food deprived rats when exposure CC1(4) was >/=25 ppm and >/=50 ppm respectively. These results indicate that consumption of ethanol and food deprivation potentiate CCl(4) induced hepatic damage even at low concentrations of CCl(4) by promoting lipid peroxidation. Thus heavy drinking may be a risk factor for CCl(4) induced hepatic damage even though the CCl(4) concentration is as low as the threshold limit value.