Repression of oxidative stress/reactive metabolite regulated gene expression is associated with conversion of carbamazepine into a hepatotoxicant in LPS and DSS rat models

• 作者: Angelique M. Leone Erin Saleh Jean McCarthy L. Mark Kao Lynn Varacallo Michael F. Kelley Michael McMillian Monica Singer Peter Taggart S. Jim Proctor
• 来源期刊: 生命科学与技术进展(英文)
• 学科: 医学
• 关键词: HEPATOTOXICITY Gene EXPRESSION Oxidative Stress/Reactive Metabolites (OS/RM) LPS DSS
• 年，卷（期）: 2014,（3）
• 页码范围: 216-229
• 页数: 14页
• 分类号: R73

摘要

Idiosyncratic hepatotoxicity accounts for many drug failures in the clinic and is a leading cause for black-boxed and withdrawn drugs. This toxicity has proven difficult to predict preclinically, but correlates with oxidative stress/reactive metabolites (OS/RM). As noted previously for antiepileptic compounds, many drugs causing idiosyncratic adverse drug effects are detected by OS/RM gene expression responses in the rat. In the present study, two immune activation models, low dose lipopolysaccharide (1 mg/kg IV) and 5% dextran sulphate sodium (DSS) in drinking water, were examined to determine if either would convert the non-toxic idiosyncratic toxicant carbamazepine (225 mg/kg) into a rat hepatotoxicant at 24 hours. Using the low dose LPS model, about 1/3 of the carbamazepine-treated rats either showed robust ALT and AST elevations with histopathological evidence of hepatotoxicity, or died. Rats in this LPS/carbamazepine group were subdivided based on ALT values into non-responders, responders or robust responders. Whereas most carbamazepine-induced mRNAs were repressed by LPS across all rats in this group, the OS/ RM genes aflatoxin aldehyde reductase (Afar) and glutathione transferase Ya (Gstya) were repressed only in the robust responder subgroup;it is unclear whether repression of these genes contributes to or results from hepatotoxicity. The OS/RM gene microsomal epoxide hydrolase (mEphx) showed repression across all rats. NAD(P)H: menadione oxidoreductase (Nmor) is an OS/RM-responsive gene that is also induced by LPS, confounding interpretation of its changes. After pretreatment with 5% DSS at 24 hours or for 5 days, using a protocol that reportedly produces increased endotoxin absorption, carbamazepine was not converted to a hepatototoxicant in any rats. Instead, DSS produced a pronounced (2- to 6-fold) and selective potentiation of carbamazepine induction of OS/RM-responsive mRNAs. The lack of repressive effects of DSS on these mRNAs or in converting carbamazepine to a hepatotoxicant was not due to dese