MALLORY BODY FORMATION BY ETHANOL FEEDING IN DRUG-PRIMED MICE

Drug-primed mice, created by a 5-month feeding of -dihydro-2,4,6-trime thyl-3,5-pyridinedicarboxylate (DDC), followed by a 1-month withdrawal , were refed ethanol or isocaloric dextrose (control) diets intragastr ically for 7 days. The formation of Mallory bodies (MBs) was monitored by immunofluorescence and immunoperoxidase microscopy using antibodie s to cytokeratin and ubiquitin, and also by electron microscopy. The c hanges in cytokeratin 55 (CK55), ubiquitin conjugate, nuclear factor k appa B (NF kappa B) p6S, NF kappa B p50, inhibitor kappa B alpha, c-my c, tumor necrosis factor alpha, and cytochrome P4SO 2E1 (CYP2E1) conte nts were determined by Western blotting using appropriate antibodies. The messenger RNA (mRNA) for CYP2E1, cytokeratin, ubiquitin, hepatocyt e growth factor activator, and tissue transglutaminase was quantitated . MBs were present at 5 to 7 days' postfeeding with ethanol, but not w ith dextrose. They developed in clusters of ''empty hepatocytes,'' whe re the cytokeratin antibody failed to recognize the typical filament s tructures seen in normal hepatocytes, MBs were larger and more numerou s in the subcapsular region. Northern blots showed that CK55 mRNA was decreased by the ethanol treatment, but protein levels were increased, suggesting a decreased turnover of the cytokeratin. Likewise, the inc rease in CYP2E1 protein in the face of a lack of an increase in mRNA f or CYP2E1 could be explained by a decreased turnover of this cytochrom e, This is the first report of MB formation induced by ethanol ingesti on in an experimental model.