Aflatoxin B1 (AFB1), a mycotoxin, is acutely hepatotoxic to many animals including humans. However, there are marked interspecies differences in sensitivity to AFB1-induced toxicity depending on bioactivation by cytochrome P450s (CYPs). In the present study, we examined the applicability of chimeric mice with humanized livers and derived fresh human hepatocytes for in vivo and vitro studies on AFB1 cytotoxicity to human hepatocytes. Chimeric mice with highly humanized livers and SCID mice received daily injections of vehicle (corn oil), AFB1 (3 mg/kg), and carbon tetrachloride (50 mg/kg) for 2 days. Histological analysis revealed that AFB1 promoted hepatocyte vacuolation and inflammatory cell infiltration in the area containing human hepatocytes. A novel human alanine aminotransferase 1 specific enzyme-linked immunosorbent assay demonstrated the acute toxicity of AFB1 to human hepatocytes in the chimeric mouse livers. The sensitivity of cultured fresh human hepatocytes isolated from the humanized liver mice for AFB1 cytotoxicity was comparable to that of primary human hepatocytes. Long-term exposure to AFB1 (6 or 14 days) produced a more severe cytotoxicity. The half-maximal lethal concentration was 10 times lower in the 2-week treatment than after 2 days of exposure. Lastly, the significant reduction of AFB1 cytotoxicity by a pan-CYP inhibitor or transfection with CYP3A4 specific siRNA clearly suggested that bioactivation of AFB1 catalyzed by CYPs was essential for AFB1 cytotoxicity to the human hepatocytes in our mouse model. Collectively, our results implicate the humanized liver mice and derived fresh human hepatocytes are useful models for studies of AFB1 cytotoxicity to human hepatocytes.

黄曲霉毒素B1（AFB1）是一种霉菌毒素，对包括人类在内的许多动物都有急性肝毒性。但是，对AFB1诱导的毒性的敏感性之间存在明显的种间差异，具体取决于细胞色素P450（CYP）的生物激活。在本研究中，我们检查了具有人源化肝脏和衍生的新鲜人肝细胞的嵌合小鼠在体内和体外的适用性AFB1对人肝细胞的细胞毒性研究。具有高度人源化肝脏的嵌合小鼠和SCID小鼠每天注射媒介物（玉米油），AFB1（3 mg / kg）和四氯化碳（50 mg / kg），持续2天。组织学分析表明，AFB1促进了人类肝细胞所在区域的肝细胞空泡化和炎性细胞浸润。一种新型的人类丙氨酸氨基转移酶1特异性酶联免疫吸附试验证明了AFB1对嵌合小鼠肝脏中人类肝细胞的急性毒性。从人源化肝小鼠分离的培养的新鲜人肝细胞对AFB1细胞毒性的敏感性与原代人肝细胞相当。长期暴露于AFB1（6或14天）产生了更严重的细胞毒性。在2周的治疗中，半数最大致死浓度比暴露2天后低10倍。最后，通过泛CYP抑制剂显着降低AFB1细胞毒性或用CYP3A4特异性siRNA转染清楚地表明，在我们的小鼠模型中，CYP催化的AFB1生物激活对于AFB1对人类肝细胞的细胞毒性至关重要。总的来说，我们的结果暗示人源化的肝小鼠和衍生的新鲜人肝细胞是用于研究AFB1对人肝细胞毒性的有用模型。