Mallory body formation by ethanol feeding in drug-primed mice

Abstract

Drug-primed mice, created by a 5-month feeding of diethyl-1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate (DDC), followed by a 1-month withdrawal, were refed ethanol or isocaloric dextrose (control) diets intragastrically for 7 days. The formation of Mallory bodies (MBs) was monitored by immunofluorescence and immunoperoxidase microscopy using antibodies to cytokeratin and ubiquitin, and also by electron microscopy. The changes in cytokeratin 55 (CK55), ubiquitin conjugate, nuclear factor B (NFB) p65, NFB p50, inhibitor B␣, c-myc, tumor necrosis factor ␣, and cytochrome P450 2E1 (CYP2E1) contents were determined by Western blotting using appropriate antibodies. The messenger RNA (mRNA) for CYP2E1, cytokeratin, ubiquitin, hepatocyte growth factor activator, and tissue transglutaminase was quantitated. MBs were present at 5 to 7 days' postfeeding with ethanol, but not with dextrose. They developed in clusters of ''empty hepatocytes,'' where the cytokeratin antibody failed to recognize the typical filament structures seen in normal hepatocytes. MBs were larger and more numerous 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 increase in CYP2E1 protein in the face of a lack of an increase in mRNA for CYP2E1 could be explained by a decreased turnover of this cytochrome. This is the first report of MB formation induced by ethanol ingestion in an experimental model. (HEPATOLOGY 1998;27:116-122.)The association between alcohol abuse and Mallory body (MB) formation in liver goes back to Mallory' s first report in 1911. 1 Mouse is the only species other than man in which MBs can be induced in response to a continuous feeding of various agents like griseofulvin and diethyl-1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate (DDC). However, attempts to induce MBs by ethanol feeding in mice have been as yet unsuccessful, perhaps because of inappropriate experimental conditions. In recent years, we set up a drug-primed mouse model to study MB formation that involved a first feeding of the drug (griseofulvin or DDC) for 5 months, followed by drug withdrawal for 1 month, and a 7-day drug refeeding. [2][3][4] Most of the MBs disappear after the drug withdrawal, leaving only small dot-like MBs at the hepatocyte periphery. However, while it takes at least 3 months of continuous drug feeding before MBs appear in naive mice, 3,4 MBs reappear after only 3 days of refeeding in drug-primed mice. We have used this mouse model to show that heat shock performed in vivo leads to MB formation. 5 Therefore, it was of major interest to determine the response of these drug-primed mice to ethanol feeding. The experimental protocol included feeding via an intragastric indwelling tube to achieve good nutrition and to maintain high blood alcohol levels. 6 The results show for the first time that alcohol ''abuse'' can induce MBs in mice in a few days using a drug-primed model. MATERIALS...

Reduced Early Alcohol-Induced Liver Injury in CD14-Deficient Mice

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Chronic ethanol feeding affects proteasome‐interacting proteins

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Keratin-mediated resistance to stress and apoptosis in simple epithelial cells in relation to health and disease

“…However, the formation pattern is kept in memory since refeeding of GF reinduces MBs within a few days (Yuan et al 1995(Yuan et al , 1996, a protocol referred to as the "drug-primed liver" model. Interestingly, reformation of MBs in drugprimed liver now occurs in response not only to GF, but also to in vivo heat treatment and alcohol feeding (Zhang-Gouillon et al 1998). These observations indicate a molecular link between chronic hepatotoxicity, MB formation, and cirrhosis, but they do not reveal if the induced K8/K18 IF aggregates are the cause or effect of the disease, nor do they provide information about the relative contribution of K8 versus K18 to MB formation.…”