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Decreased toxicity of polymorphonuclear neutrophils toward hepatocytes isolated from rats with acute inflammatory reaction
Author(s) -
Mavier Philippe,
Rosenbaum Jean,
Preaux AnneMarie,
Mallat Ariane,
Dhumeaux Daniel
Publication year - 1990
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840120614
Subject(s) - hepatocyte , cathepsin g , elastase , chemistry , zymosan , toxicity , neutrophil elastase , alanine transaminase , inflammation , biochemistry , pharmacology , biology , endocrinology , immunology , enzyme , in vitro , organic chemistry
Abstract We have recently demonstrated that polymorphonuclear neutrophils were toxic to hepatocytes through a protease‐mediated mechanism. Since synthesis of antiproteases is markedly increased during acute inflammatory reaction, the aim of this work was to investigate the toxicity of neutrophils against normal vs. inflammatory rat hepatocytes. Acute inflammatory reaction was induced by subcutaneous injection of turpentine 24 hr before the experiments. Hepatocytes from normal and turpentine‐treated rats were isolated by collagenase digestion. They were incubated with human neutrophils stimulated by 1 mg/ml opsonized zymosan. Cytotoxicity was quantified by the percentage of alanine aminotransferase activity released by hepatocytes in culture medium after an 18‐hr incubation period. By comparison to normal hepatocytes, inflammatory hepatocytes were more resistant to the toxicity of neutrophils. At a neutrophil/hepatocyte ratio of 20:1, the alanine aminotransferase activity releases were 53.7% ± 5.4% (mean ± 1 S.E.) and 27.4% ± 4.8% for normal and inflammatory hepatocytes, respectively. Similarly, inflammatory hepatocytes were found to be less sensitive than normal hepatocytes to the toxic effect of purified neutrophil cathepsin G. In contrast, both types of hepatocytes exhibited the same sensitivity to H 2 O 2 generated by a system consisting of glucose and glucose oxidase. Two arguments suggested that the resistance of inflammatory hepatocytes to protease toxicity was explained by an increased production of antiproteases by these cells: (a) when tested against cathepsin G and porcine pancreatic elastase activities, the protease inhibitory capacity of conditioned medium from inflammatory hepatocytes was higher than that of conditioned medium from normal hepatocytes; (b) conditioned medium from inflammatory hepatocytes markedly reduced the toxicity of stimulated neutrophils as that of cathepsin G. These results show that, during an acute inflammatory reaction, the increased synthesis of antiproteases by hepatocytes may inhibit the proteasemediated toxicity of neutrophils. In the clinical disorders in which a pathogenetic role of neutrophils has been suggested, the accompanying inflammatory reaction might thus have a beneficial effect by reducing neutrophil‐mediated tissue injury. (HEPATOLOGY 1990;12:1337–1341).