Department of Microbiology and Immunology, Milton S. Hershey Medical Center, The Penn State College of Medicine, Hershey, Pennsylvania 17033, USA.
Toxicol Sci. 2011 Dec;124(2):348-58. doi: 10.1093/toxsci/kfr231. Epub 2011 Sep 9.
Acetaminophen (APAP) overdose is the most frequent cause of adult acute liver failure. Susceptibility or resistance to APAP toxicity is most likely accounted for by the interplay of several factors. One factor important in multiple different chronic liver diseases that may play a role in APAP toxicity is elevated hepatic iron. Hereditary hemochromatosis is traditionally associated with hepatic iron overload. However, varying degrees of elevated hepatic iron stores observed in chronic hepatitis C and B, alcoholic liver disease and nonalcoholic fatty liver disease also have clinical relevance. We employed an animal model in which mice are fed a 3,5,5-trimethyl-hexanoyl-ferrocene (TMHF)-supplemented diet to evaluate the effect of elevated hepatic iron on APAP hepatotoxicity. Three hundred milligrams per kilogram APAP was chosen because this dosage induces hepatotoxicity but is not lethal. Since both excess iron and APAP induce oxidative stress and mitochondrial dysfunction, we hypothesized that the TMHF diet would enhance APAP hepatotoxicity. The results were the opposite. Centrilobular vacuolation/necrosis, APAP adducts, nitrotyrosine adducts, and a spike in serum alanine aminotransferase, which were observed in control mice treated with APAP, were not observed in TMHF-fed mice treated with APAP. Further analysis showed that the levels of CYP2E1 and CYP1A2 were not significantly different in TMHF-treated compared with control mice. However, the magnitude of depletion of glutathione following APAP treatment was considerably less in TMHF-treated mice than in mice fed a control diet. We conclude that a TMHF diet protects mice from moderate transient APAP-induced hepatotoxicity prior to the formation of APAP adducts, and one contributing mechanism is reduction in glutathione depletion.
对乙酰氨基酚(APAP)过量是成人急性肝衰竭最常见的原因。对 APAP 毒性的易感性或抗性最有可能是由几个因素相互作用引起的。在多种不同的慢性肝病中,一个重要的因素可能在 APAP 毒性中起作用,那就是肝铁升高。遗传性血色素沉着症传统上与肝铁过载有关。然而,慢性丙型和乙型肝炎、酒精性肝病和非酒精性脂肪性肝病中观察到的不同程度的肝铁储存升高也具有临床相关性。我们使用了一种动物模型,其中小鼠喂食 3,5,5-三甲基己酰基二茂铁(TMHF)补充饮食,以评估肝铁升高对 APAP 肝毒性的影响。选择 300 毫克/千克的 APAP,因为这种剂量会引起肝毒性,但不会致命。由于过量的铁和 APAP 都会引起氧化应激和线粒体功能障碍,我们假设 TMHF 饮食会增强 APAP 肝毒性。但结果却恰恰相反。在接受 APAP 治疗的对照组小鼠中观察到的中央小叶空泡/坏死、APAP 加合物、硝基酪氨酸加合物和血清丙氨酸氨基转移酶升高,在接受 TMHF 喂养并接受 APAP 治疗的小鼠中并未观察到。进一步分析表明,与对照组小鼠相比,TMHF 处理小鼠的 CYP2E1 和 CYP1A2 水平没有显著差异。然而,与喂食对照饮食的小鼠相比,TMHF 处理小鼠在接受 APAP 治疗后谷胱甘肽耗竭的幅度要小得多。我们得出的结论是,TMHF 饮食在形成 APAP 加合物之前可保护小鼠免受中等强度的短暂 APAP 诱导的肝毒性,一个相关的机制是减少谷胱甘肽耗竭。