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Immunohistochemical Characterization of Hepatic Malondialdehyde and 4‐Hydroxynonenal Modified Proteins During Early Stages of Ethanol‐Induced Liver Injury
Author(s) -
Sampey Brante P.,
Korourian Soheila,
Ronis Martin J.,
Badger Thomas M.,
Petersen Dennis R.
Publication year - 2003
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.2003.tb04430.x
Subject(s) - malondialdehyde , lipid peroxidation , cyp2e1 , medicine , liver injury , chemistry , hepatocyte , endocrinology , 4 hydroxynonenal , aldehyde dehydrogenase , ethanol , enteral administration , alcoholic liver disease , biochemistry , hepatic stellate cell , biology , oxidative stress , cirrhosis , parenteral nutrition , metabolism , cytochrome p450 , gene , in vitro
Background: Chronic ethanol consumption is associated with hepatic lipid peroxidation and the deposition or retention of aldehyde‐adducted proteins postulated to be involved in alcohol‐induced liver injury. The purpose of this study was to characterize hepatocellular formation of aldehyde‐protein adducts during early stages of alcohol‐induced liver injury. Methods: Female Sprague Dawley® rats were subjected to the intragastric administration of a low‐carbohydrate/high‐fat total enteral nutrition diet or a total enteral nutrition diet containing ethanol for a period of 36 days. Indexes of hepatic responses to ethanol were evaluated in terms of changes in plasma alanine aminotransferase activity, hepatic histopathologic analysis, and induction of cytochrome P‐4502E1 (CYP2E1). Immunohistochemical methods were used to detect hepatic proteins modified with malondialdehyde (MDA) or 4‐hydroxynonenal (4‐HNE) for subsequent quantitative image analysis. Results: After 36 days of treatment, rats receiving the alcohol‐containing diet displayed hepatic histopathologies characterized by marked micro‐ and macrosteatosis associated with only minor inflammation and necrosis. Alcohol administration resulted in a 3‐fold elevation of plasma alanine aminotransferase activity and 3‐fold increases ( p < 0.01) in hepatic CYP2E1 apoprotein and activity. Quantitative immunohistochemical analysis revealed significant ( p < 0.01) 5‐fold increases in MDA‐ and 4‐HNE modified proteins in liver sections prepared from rats treated with alcohol. The MDA‐ or 4‐HNE modified proteins were contained in hepatocytes displaying intact morphology and were colocalized primarily with microvesicular deposits of lipid. Aldehyde‐modified proteins were not prevalent in parenchymal or nonparenchymal cells associated with foci of necrosis or inflammation. Conclusions: These results suggest that alcohol‐induced lipid peroxidation is an early event during alcohol‐mediated liver injury and may be a sensitizing event resulting in the production of bioactive aldehydes that have the potential to initiate or propagate ensuing proinflammatory or profibrogenic cellular events.