Tsou Tsui-Chun, Yeh Szu Ching, Tsai Feng-Yuan, Chang Louis W
Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Kaohsiung, Taiwan, Republic of China.
Chem Res Toxicol. 2004 Feb;17(2):208-17. doi: 10.1021/tx034202v.
In this study, we used porcine aortic endothelial cells (PAECs) as an in vitro system to investigate the role of intracellular GSH status in arsenite-induced vascular endothelial damage. Exposure of PAECs to l-buthionine sulfoximine (BSO), an inhibitor of gamma-glutamylcysteine synthetase (gamma-GCS), markedly enhanced the arsenite-induced cytotoxicity. The data implied that intracellular GSH might play an important role in protection of PAECs from arsenite-induced cytotoxicity. Low concentrations of arsenite exposure increased intracellular GSH concentrations, whereas high concentrations of arsenite exposure decreased intracellular GSH concentrations. We further modulated intracellular GSH concentration by using GSH modulators. N-Acetyl cysteine (NAC) and l-cystine (oxidized l-cysteine), by up-regulating intracellular GSH concentrations, were shown to protect PAECs from arsenite-induced cytotoxicity. On the other hand, BSO and monosodium glutamate (MSG), which down-regulated the intracellular GSH concentrations, further potentiated arsenite-induced cytotoxicity. Moreover, exposure of PAECs to NAC alleviated the arsenite-induced JNK/AP-1 activation and apoptosis, whereas exposure of PAECs to BSO enhanced the arsenite-induced JNK/AP-1 activation and apoptosis. These results indicated that an increase in GSH content represented one of the detoxification mechanisms responding to arsenite exposure and probably played critical roles in the regulation of stress-response signaling molecules as well as in protection of PAECs from arsenite attack.
在本研究中，我们使用猪主动脉内皮细胞（PAECs）作为体外系统，以研究细胞内谷胱甘肽（GSH）状态在亚砷酸盐诱导的血管内皮损伤中的作用。将PAECs暴露于γ-谷氨酰半胱氨酸合成酶（γ-GCS）的抑制剂L-丁硫氨酸亚砜胺（BSO），可显著增强亚砷酸盐诱导的细胞毒性。数据表明，细胞内GSH可能在保护PAECs免受亚砷酸盐诱导的细胞毒性方面发挥重要作用。低浓度亚砷酸盐暴露可增加细胞内GSH浓度，而高浓度亚砷酸盐暴露则降低细胞内GSH浓度。我们进一步使用GSH调节剂调节细胞内GSH浓度。N-乙酰半胱氨酸（NAC）和L-胱氨酸（氧化型L-半胱氨酸）通过上调细胞内GSH浓度，显示出可保护PAECs免受亚砷酸盐诱导的细胞毒性。另一方面，下调细胞内GSH浓度的BSO和谷氨酸钠（MSG）进一步增强了亚砷酸盐诱导的细胞毒性。此外，将PAECs暴露于NAC可减轻亚砷酸盐诱导的JNK/AP-1激活和细胞凋亡，而将PAECs暴露于BSO则增强了亚砷酸盐诱导的JNK/AP-1激活和细胞凋亡。这些结果表明，GSH含量的增加代表了对亚砷酸盐暴露的一种解毒机制，可能在应激反应信号分子的调节以及保护PAECs免受亚砷酸盐攻击方面发挥关键作用。
