Division of Systems Biology, Food and Drug Administration/National Center for Toxicological Research, Jefferson, AR 72079, USA.
J Pharmacol Exp Ther. 2012 Feb;340(2):360-8. doi: 10.1124/jpet.111.187948. Epub 2011 Nov 1.
The role of protein glutathionylation in acetaminophen (APAP)-induced liver injury was investigated in this study. A single oral gavage dose of 150 or 300 mg/kg APAP in B6C3F1 mice produced increased serum alanine aminotransferase and aspartate aminotransferase levels and liver necrosis in a dose-dependent manner. The ratio of GSH to GSSG was decreased in a dose-dependent manner, suggesting that APAP produced a more oxidizing environment within the liver. Despite the increased oxidation state, the level of global protein glutathionylation was decreased at 1 h and continued to decline through 24 h. Immunohistochemical localization of glutathionylated proteins showed a complex dynamic change in the lobule zonation of glutathionylated proteins. At 1 h after APAP exposure, the level of glutathionylation decreased in the single layer of hepatocytes around the central veins but increased mildly in the remaining centrilobular hepatocytes. This increase correlated with the immunohistochemical localization of APAP covalently bound to protein. Thereafter, the level of glutathionylation decreased dramatically over time in the centrilobular regions with major decreases observed at 6 and 24 h. Despite the overall decreased glutathionylation, a layer of cells lying between the undamaged periportal region and the damaged centrilobular hepatocytes exhibited high levels of glutathionylation at 3 and 6 h in all samples and in some 24-h samples that had milder injury. These temporal and zonal pattern changes in protein glutathionylation after APAP exposure indicate that protein glutathionylation may play a role in protein homeostasis during APAP-induced hepatocellular injury.
本研究探讨了蛋白质谷胱甘肽化在对乙酰氨基酚（APAP）诱导的肝损伤中的作用。B6C3F1 小鼠单次口服 150 或 300mg/kg APAP 可剂量依赖性地增加血清丙氨酸氨基转移酶和天冬氨酸氨基转移酶水平，并导致肝坏死。GSH 与 GSSG 的比值呈剂量依赖性下降，表明 APAP 在肝内产生了更具氧化性的环境。尽管氧化状态增加，但在 1 小时时，总蛋白谷胱甘肽化水平下降，并持续下降至 24 小时。谷胱甘肽化蛋白的免疫组织化学定位显示，谷胱甘肽化蛋白在小叶区带的分布呈复杂的动态变化。APAP 暴露 1 小时后，中心静脉周围单层肝细胞中的谷胱甘肽化水平降低，但剩余的中央区肝细胞中的谷胱甘肽化水平轻度增加。这种增加与共价结合蛋白的 APAP 的免疫组织化学定位相关。此后，中央区的谷胱甘肽化水平随时间急剧下降，在 6 小时和 24 小时观察到明显下降。尽管整体谷胱甘肽化水平降低，但在所有样本的 3 小时和 6 小时，以及一些损伤较轻的 24 小时样本中，位于未受损的门脉周围区和受损的中央区肝细胞之间的一层细胞表现出高水平的谷胱甘肽化。APAP 暴露后蛋白质谷胱甘肽化的这些时间和区域模式变化表明，蛋白质谷胱甘肽化可能在 APAP 诱导的肝细胞损伤过程中的蛋白质稳态中发挥作用。
