cell-MB phenomenon. 6 Both compounds induce protoporphyThe aim of this study was to determine the various rin accumulation and hepatoma, 7 as well as the disturbances factors that are involved in the induction of Mallory in the cytoskeleton. Most important to the present report, body (MB) formation. A model was developed where MB the empty cell-MB phenomenon can be reproduced in days formation was induced by refeeding either of the drugs of refeeding in livers that have returned partially to normal griseofulvin or diethyl 1,4-dihydro-1,4,6-trimethyl-3,5-after 1-month withdrawal from the drugs. 1,8 pyridinedicarboxylate (DDC). Mice were fed the drugsIn the present study, mice were first primed by 5 months for 5 months, followed by withdrawal of the drugs for 1 of feeding of GF or DDC. MB formation was induced by either month (drug-primed livers). The drugs were refed for 1, GF or DDC. 9 Then, the mice were fed the diet without GF or 3, 5, 7, or 11 days. Early MBs first appeared as small, DDC for 1 month to allow the MBs to largely disappear. The enlarged aggregates of filaments in the perinuclear or mice were then refed GF or DDC for 1, 3, 5, 7, or 11 days. pericanalicular location on the third day of refeeding.The subsequent reappearance of MBs in the liver and the Mature MBs appeared on the fifth day of refeeding. MBs changes in the liver cytokeratins were measured sequenreached maximum concentration on day 5 of refeeding.tially. We found that MBs reformed beginning at 3 days of Western blots showed a progressive increase in the cytorefeeding. The liver cell cytokeratin proteins abruptly inkeratin proteins (CK49 and CK55) and actin while recreased on the third day of refeeding. Liver regeneration also feeding the drugs. Liver cell regeneration, as indicated increased on the third day of refeeding, as indicated by the by the percent of proliferating cell nuclear antigen level of proliferating cell nuclear antigen (PCNA) labeling of (PCNA)-positive nuclei, increased on the third day of hepatocytic nuclei. However, this did not correlate with the refeeding. However, there was no correlation between level of MB expression. An increase in ubiquitin conjugates, the frequency of MBs and the percent of PCNA-positive as indicated by an increase in the ubiquitin smear observed nuclei. It is concluded that MB formation is not related in Western blots made from whole liver homogenates, correto the liver cell regeneration response to injury but lated with the number of ubiquinated MBs. The results suprather involves a separate regulation pathway. The MBs port the hypothesis that ubiquitination of partially unfolded were heavily ubiquitinated and were associated with incytokeratin proteins is involved in their aggregation to form creased ubiquitin-protein conjugates as indicated byMBs. These results have been reported in part in an abWestern blotting, suggesting that ubiquitinization of cystract. 10 tokeratin protein are involved in the formation of MB aggregation. (HEPATOLOGY 1996;24:603-612.) MATERIALS AND METHODS Denk et ...

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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...