title: The role of renal proximal tubule P450 enzymes in chloroform-induced nephrotoxicity: utility of renal specific P450 reductase knockout mouse models.
abstract: The kidney is a primary target for numerous toxic compounds. Cytochrome P450 enzymes (P450) are responsible for the metabolic activation of various chemical compounds, and in the kidney are predominantly expressed in proximal tubules. The aim of this study was to test the hypothesis that renal proximal tubular P450s are critical for nephrotoxicity caused by chemicals such as chloroform. We developed two new mouse models, one having proximal tubule-specific deletion of the cytochrome P450 reductase (Cpr) gene (the enzyme required for all microsomal P450 activities), designated proximal tubule-Cpr-null (PTCN), and the other having proximal tubule-specific rescue of CPR activity with the global suppression of CPR activity in all extra-proximal tubular tissues, designated extra-proximal tubule-Cpr-low (XPT-CL). The PTCN, XPT-CL, Cpr-low (CL), and wild-type (WT) mice were treated with a single oral dose of chloroform at 200mg/kg. Blood, liver and kidney samples were obtained at 24h after the treatment. Renal toxicity was assessed by measuring BUN and creatinine levels, and by pathological examination. The blood and tissue levels of chloroform were determined. The severity of toxicity was less in PTCN and CL mice, compared with that of WT and XPT-CL mice. There were no significant differences in chloroform levels in the blood, liver, or kidney, between PTCN and WT mice, or between XPT-CL and CL mice. These findings indicate that local P450-dependent activities play an important role in the nephrotoxicity induced by chloroform. Our results also demonstrate the usefulness of these novel mouse models for studies of chemical-induced kidney toxicity.
authors.affiliation: Kidney Institute & Division of Nephrology, Changzheng Hospital, Shanghai 200003, China; Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York, Albany, NY 12201, USA.
authors.forename: Senyan
authors.initials: S
authors.lastname: Liu
authors.forename: Yunyi
authors.initials: Y
authors.lastname: Yao
authors.forename: Shijun
authors.initials: S
authors.lastname: Lu
authors.forename: Kenneth
authors.initials: K
authors.lastname: Aldous
authors.forename: Xinxin
authors.initials: X
authors.lastname: Ding
authors.forename: Changlin
authors.initials: C
authors.lastname: Mei
authors.forename: Jun
authors.initials: J
authors.lastname: Gu
mesh_terms: D000818:Animals; D001806:Blood Urea Nitrogen; D015153:Blotting, Western; D002460:Cell Line; D002725:Chloroform / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*; D003404:Creatinine / Q000097:blood; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics; D007668:Kidney / Q000473:pathology; D007674:Kidney Diseases / Q000139:chemically induced* / Q000201:enzymology*; D007687:Kidney Tubules, Proximal / Q000201:enzymology*; D051379:Mice; D018345:Mice, Knockout; D009251:NADPH-Ferrihemoprotein Reductase / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D014018:Tissue Distribution
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D002725:Chloroform; D003577:Cytochrome P-450 Enzyme System; D003404:Creatinine; D009251:NADPH-Ferrihemoprotein Reductase
keywords: ALT; BUN; CPR; Chloroform; Cytochrome P450; Gene knockout; Mice; NADPH-cytochrome P450 reductase; Nephrotoxicity; P450 or CYP; P450 reductase; Scr; alanine aminotransferase; blood urea nitrogen; cytochrome P450; serum creatinine