Abstract：
Triazole fungicides such as propiconazole (Pi) or tebuconazole (Te) show hepatotoxicity in vivo, e.g., hypertrophy and vacuolization of liver cells following interaction with nuclear receptors such as PXR (pregnane-X-receptor) and CAR (constitutive androstane receptor). Accordingly, azoles affect gene expression associated with these adverse outcomes in vivo but also in human liver cells in vitro. Additionally, genes indicative of liver cholestasis are affected in vivo and in vitro. We therefore analyzed the capability of Pi and Te to cause cholestasis in an adverse outcome pathway (AOP)-driven approach in hepatic cells of human origin in vitro, considering also previous in vivo studies. Bile salt export pump (BSEP) activity assays confirmed that both azoles are weak inhibitors of BSEP. They alternate the expression of various cholestasis-associated target genes and proteins as well as the mitochondrial membrane function. Published in vivo data, however, demonstrate that neither Pi nor Te cause cholestasis in rodent bioassays. This discrepancy can be explained by the in vivo concentrations of both azoles being well below their EC50 for BSEP inhibition. From a regulatory perspective, this illustrates that toxicogenomics and human in vitro models are valuable tools to detect the potential of a substance to cause a specific type of toxicity. To come to a sound regulatory conclusion on the in vivo relevance of such a finding, results will have to be considered in a broader context also including toxicokinetics in a weight-of-evidence approach.
摘要：
三唑类杀真菌剂如丙环唑（Pi）或戊唑醇（Te）在体内显示肝毒性，例如，与核受体如PXR（孕烷X受体）和CAR（组成型雄甾烷受体）相互作用后，肝细胞肥大和空泡化。因此，唑类药物在体内影响与这些不良后果相关的基因表达，在体外也影响人肝细胞。此外,指示肝胆汁淤积的基因在体内和体外都受到影响。因此，我们分析了Pi和Te在体外人类来源的肝细胞中以不良结果途径（AOP）驱动的方法引起胆汁淤积的能力，还考虑到以前的体内研究。胆盐输出泵(BSEP)活性测定证实两种唑是BSEP的弱抑制剂。它们交替表达各种胆汁淤积相关的靶基因和蛋白质以及线粒体膜功能。发表在体内的数据，然而,证明Pi和Te都不会在啮齿动物生物测定中引起胆汁淤积。这种差异可以通过两种唑的体内浓度远低于其对BSEP抑制的EC50来解释。从监管的角度来看，这说明毒性基因组学和人类体外模型是检测物质引起特定类型毒性的潜力的有价值的工具。为了对这一发现的体内相关性得出合理的监管结论，必须在更广泛的背景下考虑结果，包括证据权重方法中的毒物动力学。
