Wang Lei, Li Xiankui, Chen Cai
Department of Respinatory Medicine, First Affiliated Hospital of Zhengzhou University.
Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Tianjin Medical University.
Biomed Res. 2018;39(2):87-94. doi: 10.2220/biomedres.39.87.
Chloroform is a common contaminant in the drinking water. Exposure of human to chloroform leads to severe hepatotoxicity. In the present study, chloroform-induced acute liver injury was investigated in mice using 3-methyadenine (3-MA), a common autophagy inhibitor. At 24 h after intraperitoneal injection of 0.5 mL/kg chloroform, serum alanine aminotransferase (ALT) levels were increased significantly; extensive necrosis and inflammation occurred as identified by histological examinations. Moreover, chloroform induced an increase in lipid peroxidation as demonstrated by increased formation of malondialdehyde (MDA) in the liver tissues. Hepatic antioxidants including glutathione (GSH) and superoxide dismutase (SOD) were decreased by chloroform treatment. All these changes were significantly inhibited by 3-MA treatment. Further mechanistic insights demonstrated that chloroform up-regulated pro-inflammatory cytokine, IL-1β, in the livers and blood, which was suppressed by 3-MA. Surprisingly, Western blots results showed that after 24-hours of chloroform treatment 3-MA activated autophagy as indicated by decreased levels of LC3B II and p62 protein. Co-treatment of chloroquine with 3-MA to inhibit autophagy would abrogate the hepatoprotection of 3-MA in chloroform hepatotoxicity. Taken together, findings in the present study suggested that a widely-used autophagy inhibitor, 3-MA, significantly reduced chloroform hepatotoxicity in mice via autophagy activation. Findings in this study also suggested that caution should be exercised when using 3-MA to modulate autophagy in vivo.
氯仿是饮用水中的常见污染物。人体接触氯仿会导致严重的肝毒性。在本研究中，使用常见的自噬抑制剂3-甲基腺嘌呤（3-MA）在小鼠中研究氯仿诱导的急性肝损伤。腹腔注射0.5 mL/kg氯仿后24小时，血清丙氨酸转氨酶（ALT）水平显著升高；组织学检查显示出现广泛坏死和炎症。此外，肝脏组织中丙二醛（MDA）形成增加表明氯仿诱导脂质过氧化增加。氯仿处理使包括谷胱甘肽（GSH）和超氧化物歧化酶（SOD）在内的肝脏抗氧化剂减少。3-MA处理可显著抑制所有这些变化。进一步的机制研究表明，氯仿上调肝脏和血液中的促炎细胞因子IL-1β，而3-MA可抑制这种上调。令人惊讶的是，蛋白质免疫印迹结果显示，氯仿处理24小时后，3-MA激活了自噬，表现为LC3B II和p62蛋白水平降低。氯喹与3-MA共同处理以抑制自噬会消除3-MA对氯仿肝毒性的肝脏保护作用。综上所述，本研究结果表明，一种广泛使用的自噬抑制剂3-MA通过激活自噬显著降低了小鼠的氯仿肝毒性。本研究结果还表明，在体内使用3-MA调节自噬时应谨慎。
