Original Contribution THE CYP INHIBITOR 1-AMINOBENZOTRIAZOLE DOES NOT PREVENT OXIDATIVE STRESS ASSOCIATED WITH ALCOHOL-INDUCED LIVER INJURY IN RATS AND MICE FUYUMI ISAYAMA,* MATTHIAS FROH,* BLAIR U. BRADFORD,* STEPHEN E. MCKIM,* MARIA B. KADIISKA, † HENRY D. CONNOR, † RONALD P. MASON, † DENNIS R. KOOP, ‡ MICHAEL D. WHEELER,* and GAVIN E. ARTEEL* ,§ *Laboratory of Hepatobiology and Toxicology, Department of Pharmacology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; † Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC, USA; ‡ Department of Physiology and Pharmacology, Oregon Health Sciences University, Portland, OR, USA; and § Department of Pharmacology and Toxicology, University of Louisville, Louisville KY, USA (Received 1 May 2003; Revised 28 August 2003; Accepted 5 September 2003) Abstract—Cytochrome P450 (CYP) 2E1 is induced by ethanol and is postulated to be a source of reactive oxygen species during alcoholic liver disease. However, there was no difference in liver pathology and radical formation between wild-type and CYP2E1 knockout mice fed ethanol. Other CYP isoforms may contribute these effects if CYP2E1 is inhibited or absent. The purpose of this study was, therefore, to determine if blocking most of the P450 isoforms with 1-aminobenzotriazole (ABT; 100 mg/kg i.g.), has any effect on liver damage and oxidative stress due to alcohol in rats and mice. Male C57BL/6 mice and Wistar rats were fed either high-fat control or ethanol-containing enteral diet for 4 weeks. ABT had a significant inhibitory effect on many P450 isoforms independent of concomitant alcohol administration. However, ABT did not protect against liver damage due to alcohol in either species. Indices of oxidative stress and inflammation were also similar in livers from vehicle-treated and ABT-treated animals fed ethanol. In summary, suppression of P450 activity with ABT had no apparent effect on oxidative stress caused by alcohol in both rats and mice. These data support the hypothesis that oxidative stress and liver damage can occur independently of CYP activities in both rats and mice during early alcohol-induced liver injury. © 2003 Elsevier Inc. Keywords—Electron spin-resonance, Alcohol, 4-Hydroxynonenal, Liver disease, Free radicals INTRODUCTION It has been well documented that alcoholic liver disease results from the dose- and time-dependent consumption of alcohol [1]. This disease is the fourth-leading cause of death in urban U.S. males [2,3]. It is characterized by steatosis, inflammation, necrosis, and ultimately fibrosis and cirrhosis. Unfortunately, mechanisms of alcohol- induced liver injury have yet to be clearly understood in spite of numerous hypotheses. Dietary manipulation and controlled enteral administration of ethanol using tech- niques developed by Tsukamoto and French now make it possible to produce pathological changes in the rodent liver that resemble early alterations of human alcoholic liver disease [4]. Furthermore, this model has been mod- ified to test the effect of specific genetic alterations in knockout mice [5]. The involvement of oxidative stress in alcohol-in- duced liver injury has long been studied [6]. The spin trapping technique has provided both in vitro [7,8] and in vivo [9] evidence for a free radical derived from ethanol, the -hydroxyethyl radical. It was recently shown that delivery of Cu/Zn-superoxide dismutase (SOD) via ade- novirus (Ad) prevented alcohol-induced liver injury and -hydroxyethyl radical formation [10]. Gene delivery of SOD with Ad [10] clearly demonstrates a role for super- oxide (O 2 •- ) in alcohol-induced liver injury and oxida- tive stress, but the source is unclear because there are many superoxide-producing enzymes in vivo. Potential Address correspondence to: Gavin Arteel, Ph.D., Department of Pharmacology and Toxicology, University of Louisville Health Sci- ences Center, Room 1306, Research Tower 500, South Preston Street, Louisville, KY 40292, USA; Tel: (502) 852-5157; Fax: (502) 852- 3242; E-Mail: gavin.arteel@louisville.edu. Free Radical Biology & Medicine, Vol. 35, No. 12, pp. 1568 –1581, 2003 Copyright © 2003 Elsevier Inc. Printed in the USA. All rights reserved 0891-5849/03/$–see front matter doi:10.1016/j.freeradbiomed.2003.09.007 1568