Modes of cell death in rat liver after monocrotaline exposure
Modes of cell death in rat liver after monocrotaline exposure
复制标题
DOI：
10.1093/toxsci/kfh011
复制
发表时间：
2004-01-01
影响因子：
3.8
通讯作者：
Roth, RA
中科院分区：
文献类型：
--
作者：
Copple, BL;Rondelli, CM;Roth, RA
野百合碱（MCT）是一种吡咯里西啶生物碱（PA）植物毒素，可导致大鼠肝脏小叶中心区窦状隙内皮细胞（SEC）损伤、出血、纤维蛋白沉积和凝固性肝实质细胞（HPC）胀亡。在暴露于其他PA的动物肝脏中观察到具有凋亡形态的细胞。尚不清楚MCT给药动物的肝脏中是否发生细胞凋亡，以及其是否是病理变化完全表现所必需的。为了确定这一点，大鼠接受300 mg MCT/kg给药，并通过透射电子显微镜和TUNEL（TdT介导的dUTP缺口末端标记）试验检测细胞凋亡。MCT在处理后4 h在肝脏中产生显著的细胞凋亡。为了确定MCT是否通过细胞凋亡杀死培养的HPC，从大鼠肝脏中分离HPC并暴露于MCT。MCT引起丙氨酸氨基转移酶（ALT）（HPC损伤的标志物）的浓度依赖性释放。此外，在MCT处理的HPC中，caspase 3被激活，TUNEL染色增加。MCT诱导的TUNEL染色和ALT向培养基中的释放被泛胱天蛋白酶抑制剂z-VAD. favoritol和IDN-7314完全阻止，表明MCT通过细胞凋亡杀死培养的HPC。为确定半胱天冬酶抑制是否可预防MCT诱导的肝脏细胞凋亡，对大鼠进行MCT和IDN-7314联合给药。IDN-7314减少肝脏中MCT诱导的TUNEL染色和ALT释放到血浆中。形态测定分析证实，IDN-7314使肝脏中的HPC胀亡减少约50%。由于HPC缺氧发生在MCT处理动物的肝脏中，因此检查了缺氧调节的细胞死亡因子BNIP 3（Bcl 2/腺病毒EIB 19 kD相互作用蛋白3）的上调。在24小时前用MCT处理的小鼠的肝脏中BNIP 3增加。这些研究的结果表明，MCT通过凋亡杀死培养的HPC，但在体内引起肝脏中的胀亡和凋亡。此外，半胱天冬酶抑制可减少MCT暴露后肝脏中的细胞凋亡和HPC胀亡。
Monocrotaline (MCT) is a pyrrolizidine alkaloid (PA) plant toxin that produces sinusoidal endothelial cell (SEC) injury, hemorrhage, fibrin deposition, and coagulative hepatic parenchymal cell (HPC) oncosis in centrilobular regions of rat livers. Cells with apoptotic morphology have been observed in the livers of animals exposed to other PAs. Whether apoptosis occurs in the livers of MCT-treated animals and whether it is required for full manifestation of pathological changes is not known. To determine this, rats were treated with 300 mg MCT/kg, and apoptosis was detected by transmission electron microscopy and the TUNEL (TdT-mediated dUTP nick end labeling) assay. MCT produced significant apoptosis in the liver by 4 h after treatment. To determine if MCT kills cultured HPCs by apoptosis, HPCs were isolated from the livers of rats and exposed to MCT. MCT caused a concentration-dependent release of alanine aminotransferase (ALT), a marker of HPC injury. Furthermore, caspase 3 was activated and TUNEL staining increased in MCT-treated HPCs. MCT-induced TUNEL staining and release of ALT into the medium were completely prevented by the pancaspase inhibitors z-VAD.fmk and IDN-7314, suggesting that MCT kills cultured HPCs by apoptosis. To determine if caspase inhibition prevents MCT-induced apoptosis in the liver, rats were cotreated with MCT and IDN-7314. IDN-7314 reduced MCT-induced TUNEL staining in the liver and release of ALT into the plasma. Morphometric analysis confirmed that IDN-7314 reduced HPC oncosis in the liver by approximately 50%. Inasmuch as HPC hypoxia occurred in the livers of MCT-treated animals, upregulation of the hypoxia-regulated cell-death factor, BNIP3 (Bcl2/adenovirus EIB 19kD-interacting protein 3), was examined. BNIP3 was increased in the livers of mice treated 24 h earlier with MCT. Results from these studies show that MCT kills cultured HPCs by apoptosis but causes both oncosis and apoptosis in the liver in vivo. Furthermore, caspase inhibition reduces both apoptosis and HPC oncosis in the liver after MCT exposure.