Induction of cytochrome P450 2E1 increases hepatotoxicity caused by Fas agonistic Jo2 antibody in mice†

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Abstract
Cytochrome P450 2E1 (CYP2E1) may be a central pathway in generating oxidative stress, reactive oxygen species, and causing hepatotoxic injury by alcohol and various hepatotoxins. This study evaluated the ability of CYP2E1 to potentiate or synergize the hepatotoxicity of Fas in vivo. C57BL/6 mice were injected intraperitoneally with pyrazole (Pyr) to induce CYP2E1. Then, 16-hour fasted mice were administered agonistic Jo2 anti-Fas antibody ip. Other mice were treated with Pyr or Jo2 alone. Levels of serum aminotransferase were 8.3- and 6.3-fold higher in the Pyr/Jo2 group compared with Jo2 alone, respectively. Histological evaluation of liver showed more extensive acidophilic necrosis and severe pathological changes in the Pyr/Jo2-treated mice. DNA fragmentation and caspase-8 and -3 activities were more elevated in the Pyr/Jo2 group compared with Jo2 alone. CYP2E1 activity and protein levels were higher in the Pyr/Jo2 group than in Jo2 alone. Levels of inducible nitric oxide synthase, 3-nitrotyrosine protein adducts, malondialdehyde, and protein carbonyls were also higher in the Pyr/Jo2 group compared with Jo2 alone. Glutathione and activities of catalase and Cu-Zn superoxide dismutase were decreased in the Pyr/Jo2 group. Administration of chlormethiazole, an inhibitor of CYP2E1, to the Pyr/Jo2-treated mice caused a significant decrease of alanine aminotransferase and liver pathological changes in association with a decrease in CYP2E1 protein and activity. In conclusion, enhanced hepatotoxicity of Fas was found in mice with elevated levels of CYP2E1. We speculate that overexpression of CYP2E1 might synergize and increase the susceptibility to Fas induced-liver injury. (HEPATOLOGY 2005;42:400–410.)