Department of Pharmacology, Toxicology, and Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
Toxicol Sci. 2010 May;115(1):286-94. doi: 10.1093/toxsci/kfq042. Epub 2010 Feb 4.
Alpha-naphthylisothiocyanate (ANIT) causes cholestatic hepatitis characterized by intrahepatic bile duct epithelial cell injury and periportal hepatocellular necrosis. The progression of ANIT-induced hepatocyte injury is reported to involve extrahepatic cells including platelets. We showed recently that the procoagulant protein tissue factor (TF) is essential for ANIT-induced coagulation and contributes to ANIT-induced liver necrosis. Platelets have been shown to express TF and can contribute to coagulation cascade activation. To this end, we tested the hypothesis that platelet-dependent coagulation contributes to ANIT-induced liver injury. In ANIT (60 mg/kg)-treated mice, activation of the coagulation cascade occurred prior to a decrease of platelets in the blood. Immunostaining for glycoprotein IIb (CD41) revealed platelet accumulation along the borders of necrotic foci in livers of ANIT-treated mice. Antibody-mediated platelet depletion did not affect coagulation but markedly affected liver histopathology in ANIT-treated mice. Platelet depletion induced marked pooling of blood within necrotic lesions consistent with parenchymal-type peliosis as early as 24 h after ANIT treatment. In contrast, treatment with the P2Y(12) inhibitor clopidogrel significantly reduced ANIT-induced hepatocyte necrosis and serum alanine aminotransferase activity but did not exaggerate bleeding into necrotic foci. Clopidogrel also reduced hepatic neutrophil accumulation but did not affect induction of Intercellular adhesion molecule-1 or chemokine CxC motif ligand-1 messenger RNA expression in liver. The data indicate that ANIT-induced coagulation is platelet independent and that platelets contribute to ANIT-induced hepatocyte necrosis by promoting neutrophil accumulation. In contrast, severe thrombocytopenia induces parenchymal-type peliosis in the livers of ANIT-treated mice, a rare hepatic lesion associated with pooling of blood in the liver.
α-萘基异硫氰酸酯（ANIT）可引起胆汁淤积性肝炎，其特征为肝内胆管上皮细胞损伤和门脉周围肝细胞坏死。据报道，ANIT 诱导的肝细胞损伤的进展涉及包括血小板在内的肝外细胞。我们最近表明，促凝蛋白组织因子（TF）对于 ANIT 诱导的凝血是必需的，并且有助于 ANIT 诱导的肝坏死。已有研究表明血小板表达 TF 并能促进凝血级联激活。为此，我们检验了血小板依赖性凝血是否有助于 ANIT 诱导的肝损伤的假说。在 ANIT（60mg/kg）处理的小鼠中，凝血级联的激活发生在血液中血小板减少之前。免疫组织化学染色糖蛋白 IIb（CD41）显示血小板在 ANIT 处理小鼠肝脏的坏死灶边缘积聚。抗体介导的血小板耗竭不影响凝血，但显著影响 ANIT 处理小鼠的肝组织病理学。血小板耗竭在 ANIT 处理后 24 小时内就会导致坏死病变内的血液明显淤积，这与实质型血窦扩张一致。相比之下，P2Y（12）抑制剂氯吡格雷的治疗显著减少了 ANIT 诱导的肝细胞坏死和血清丙氨酸氨基转移酶活性，但并没有加重坏死灶内的出血。氯吡格雷还减少了肝中性粒细胞的积聚，但不影响肝内细胞间黏附分子-1 或趋化因子 CXC 基元配体-1 信使 RNA 的诱导。数据表明，ANIT 诱导的凝血与血小板无关，而血小板通过促进中性粒细胞积聚来促进 ANIT 诱导的肝细胞坏死。相反，严重的血小板减少症会导致 ANIT 处理小鼠的肝脏发生实质型血窦扩张，这是一种罕见的肝脏病变，与肝脏内血液淤积有关。
