Novel protective mechanisms for cholestatic hepatotoxicity-application to drug improving hepatic function

给实验动物注射石胆酸(LCA)会导致迟发性淤胆性肝损伤。通过与孕烯醇酮-16α-碳腈(PCN)或喹卡林共处理小鼠，分析了LCA诱导的肝损伤的保护机制。首先，我们试图通过基因芯片分析来探索一种新的保护LCA所致胆汁淤积性肝损伤的机制。分析了饲喂0.6%LCA饲料3天(LCA3)、5天(LCA5)和9天(LCA9)的小鼠肝脏基因表达和肝损伤诊断标志物的时间依赖性变化。LCA5和LCA9的血清丙氨酸氨基转移酶和碱性磷酸酶活性分别显著升高。在芯片检测的8451个探针中，57个(LCA3)、271个(LCA5)和1426个(LCA9)与对照组相比变化了2倍以上。在这项研究中，我们重点研究了脂代谢和转运。Lca5和L…中膜联蛋白A2和磷脂扰乱酶1的表达水平显著升高更多的CA9。LCA9的磷脂酸酸性磷酸酶2 A、2 C和脂蛋白脂酶的表达也增加。在LCA9中，肝脏和血浆之间的脂质转移相关基因的表达也发生了显著的变化。另一方面，在喂食β的小鼠中，与能量产生系统有关的基因表达下降，如三氯乙酸氧化和三氯乙酸循环，并呈时间依赖关系。这些数据表明，LCA喂养的小鼠的脂质代谢和运输受到干扰。在用孕烯醇酮-16a-碳腈(PCN)联合治疗的小鼠中，这些变化消失了，PCN可以保护LCA诱导的毒性。LCA9组小鼠肝脏磷脂、三酰甘油和胆汁磷脂浓度降低，而LCA/PCN联合治疗组小鼠肝磷脂、三酰甘油和胆汁磷脂浓度升高。此外，与磷脂酶A2抑制剂奎纳克林联合治疗可减轻LCA诱导的肝损伤，增加肝脏磷脂浓度。提示肝磷脂水平升高是LCA致胆汁淤积性肝损伤的保护机制之一。较少

Lithocholic acid (LCA) administration to experimental animals is known to cause delayed cholestatic liver injury. Protective mechanisms of LCA-induced liver damage were analyzed by co-treatment of mice with pregnenolone-16 a -carbonitrile (PCN) or quinacrine. First, we tried to explore a novel protective mechanism for LCA-induced cholestatic liver injury using microarray analysis. Time-dependent changes in gene expression and liver damage diagnostic markers were analyzed in mice fed a 0.6% LCA diet for 3 days (LCA3), 5 days (LCA5) and 9 days (LCA9). Significant increases in serum alanine aminotransferase and alkaline phosphatase activities were found in LCA5 and LCA9, respectively. More than 2-fold changes relative to control group were found in 57 (LCA3), 271 (LCA5) and 1426 (LCA9) out of 8451 probes in microarray assays. In this study, we have focused on lipid metabolism and transport. Expression levels of annexin A2 and phospholipid scramblase 1 were markedly increased in LCA5 and L … More CA9. Those of phosphatidic acid phosphatase 2A, 2C and lipoprotein lipase were also increased in LCA9. Marked changes in gene expression involved in lipid transfer between liver and plasma were also found in LCA9. On the other hand, decreases in gene expression involved in the energy production system such as β-oxidation and TCA cycle were observed in a time-dependent manner in LCA-fed mice. These data suggest disruption of lipid metabolism and transport in LCA-fed mice. These changes disappeared in mice co-treated with pregnenolone-16 a-carbonitrile (PCN) which protects against LCA-induced toxicity. Hepatic phospholipid, triacylglycerol and biliary phospholipid concentrations were decreased in LCA9, whereas the concentrations were increased in LCA/PCN co-treated mice. Furthermore, co-treatment of mice with phospholipase A2 inhibitor, quinacrine decreased LCA-induced liver injury and increased hepatic phospholipids concentration. These results suggest that the enhancement of hepatic phospholipids level is one of the protective mechanisms for LCA-induced cholestatic liver injury. Less