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Elucidation of Mechanism of Drug-Induced Liver Injury Based on Danger Hypothesis

基于危险假说阐明药物性肝损伤机制

基本信息

批准号：
18590153
负责人：
MASUBUCHI Yasuhiro
金额：
$ 2.57万
依托单位：
Chiba Institute of Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Animal models of inflammatory bowel disease were subjected to characterization of liver function under inflammatory conditions. Rats were treated intracolonically with 100 mg/kg trinitrobenzene sulfonic acid (TNBS), which induced hemorrhagic colitis. The colitis accompanies appearance of higher levels of portal endotoxin, interleukin-6 and nitric oxide metabolites, and decreases in contents and activities for hepatic CYP3A2. Nimesulide, a preferential COX-2 inhibitor protected rats with TNBS-colitis against the down-regulation of hepatic CYP3A2. Polymyxin B, which neutralizes endotoxin, curcumin, which has anti-inflammatory properties, and gadolinium chloride, which inactivates macrophages, attenuated the down-regulation of CYP3A2. These data suggest that endogenous substances leaked from damaged colon in the rats with TNBS-colitis activate Kupffer cells, leading to down-regulation of hepatic P450s. It is thus proposed that gut-derived inflammatory stimuli behave as "danger signal" in drug-induced liver effects. In other studies, role of covalent adduct in diclofenac hepatotoxicity was assessed by measuring metabolism-dependent covalent binding to hepatic microsomes from various animal species. Covalent binding [14C]diclofenac- derived radioactivity to microsomal protein after incubation with NADPH was higher in rats and mice than in humans. Similar to diclofenac '5-hydroxylation, the metabolism-dependent covalent binding was higher in male rats than in females, whereas this activity in human is very low. GSH, which lowers covalent binding, was more effective in male mice than in male rats. Thus, reactive metabolites can reach proteins other than P450 effectively in mice and may lead to hepatotoxicity, which was confirmed by in vivo study developing diclofenac-induced liver injury in mice. These findings suggest that both covalent binding to the specific targets and subsequent inflammatory stimuli are responsible for drug-induced hepatotoxicity.

炎症性肠病动物模型在炎症条件下进行肝功能表征。采用100 mg/kg三硝基苯磺酸（TNBS）结肠内灌胃，诱导出血性结肠炎。结肠炎伴门静脉内毒素、白细胞介素-6和一氧化氮代谢产物水平升高，肝脏CYP3A2含量和活性降低。尼美舒利是一种优先的COX-2抑制剂，可保护tnbs -结肠炎大鼠免受肝脏CYP3A2下调的影响。中和内毒素的多粘菌素B，具有抗炎特性的姜黄素，以及灭活巨噬细胞的氯化钆，减弱了CYP3A2的下调。这些数据表明，tnbs -结肠炎大鼠受损结肠泄漏的内源性物质激活Kupffer细胞，导致肝脏p450下调。因此，提出肠道来源的炎症刺激在药物诱导的肝脏效应中充当“危险信号”。在其他研究中，共价加合物在双氯芬酸肝毒性中的作用是通过测量代谢依赖的共价与不同动物肝微粒体的结合来评估的。大鼠和小鼠与NADPH孵育后双氯芬酸衍生的微粒体蛋白的共价结合[14C]放射性高于人。与双氯芬酸5-羟基化相似，雄性大鼠的代谢依赖性共价结合高于雌性大鼠，而人类的这种活性非常低。降低共价结合的谷胱甘肽在雄性小鼠中比在雄性大鼠中更有效。因此，反应性代谢物可以在小鼠体内有效到达P450以外的蛋白质，并可能导致肝毒性，这在双氯芬酸诱导小鼠肝损伤的体内研究中得到证实。这些发现表明，与特定靶点的共价结合和随后的炎症刺激都是药物诱导的肝毒性的原因。