AN IN-VITRO MODEL OF ETHANOL-DEPENDENT LIVER-CELL INJURY

Primary cultures of adult rat hepatocytes were incubated (6 to 96 hr) with 50 to 150 mmol/L ethanol, 0.5 mmol/L linoleate, 0.5 mmol/L palmit ate, 0.5 mmol/L 4-methylpyrazole, 0 to 25 mumol/L vitamin E phosphate or selected combinations of these agents. Agent-dependent changes in l iver cell viability (AST release and reduction of (4,5-dimethylthiazol -2-yl)-2,5-diphenyltetrazolium bromide) and function (phospholipid per oxidation, hydrolysis, biosynthesis and triacylglycerol biosynthesis) were determined. The influence of ethanol on liver cell function and v iability was dose and incubation time dependent. Short periods (24 hr or less) of exposure to 100 mmol/L ethanol increased liver cell triacy lglycerol biosynthesis and phospholipid hydrolysis, peroxidation and b iosynthesis without altering cell viability. However, longer periods ( 72 hr or more) of exposure to 100 or 150 mmol/L ethanol resulted in si gnificant reductions (30% to 50%) in cell viability, function and phos phatidylcholine biosynthesis and content. The ethanol-dependent decrea ses in cell function and viability were potentiated by linoleate and r educed by vitamin E phosphate, palmitate and 4-methylpyrazole. These r esults suggest that ethanol-induced liver cell injury in vitro is not a result of ethanol per se, but factors such as acetaldehyde or oxyrad icals produced as a consequence of ethanol metabolism. Therefore the i ncubation of cultured hepatocytes with ethanol may be an appropriate m odel in vitro for determining the mechanisms by which ethanol intake d isrupts liver cell function in vivo.