Vascular and hepatocellular peroxynitrite formation during acetaminophen toxicity: Role of mitochondrial oxidant stress
Vascular and hepatocellular peroxynitrite formation during acetaminophen toxicity: Role of mitochondrial oxidant stress
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DOI：
10.1093/toxsci/62.2.212
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发表时间：
2001-08-01
影响因子：
3.8
通讯作者：
Jaeschke, H
中科院分区：
文献类型：
--
作者：
Knight, TR;Kurtz, A;Jaeschke, H
过氧亚硝酸盐可能与对乙酰氨基酚引起的肝损伤有关。然而，尚不清楚过氧亚硝酸盐是在肝细胞中还是在脉管系统中产生。为了解决这个问题，我们用 300 mg/kg 对乙酰氨基酚治疗 C3Heb/FeJ 小鼠，并评估硝基酪氨酸蛋白加合物作为过氧亚硝酸盐形成的指标。对乙酰氨基酚治疗后 0.5 至 2 小时内，肝损伤前血管硝基酪氨酸染色很明显。然而，在对乙酰氨基酚后 2 至 6 小时内，肝损伤与肝细胞硝基酪氨酸染色同时发生。作为活性氧形成指标的谷胱甘肽二硫化物的线粒体含量在对乙酰氨基酚后 6 小时测定，从对照组的 2.8 +/- 0.6% 增加到 23.5 +/- 5.1%。高剂量的别嘌呤醇（100 mg/kg）强烈减弱对乙酰氨基酚蛋白加合物的形成，并防止对乙酰氨基酚后的线粒体氧化应激和肝损伤。较低剂量的别嘌呤醇在抑制黄嘌呤氧化酶方面同样有效，但没有保护作用，并且对硝基酪氨酸染色和对乙酰氨基酚蛋白加合物的形成没有影响。体外实验表明别嘌呤醇不是过氧亚硝酸盐的直接清除剂。我们得出的结论是，在对乙酰氨基酚治疗后的前 2 小时内，存在血管过氧亚硝酸盐形成。另一方面，对乙酰氨基酚的反应性代谢物与细胞内蛋白质结合，导致线粒体功能障碍和超氧化物形成。线粒体超氧化物与一氧化氮反应形成过氧亚硝酸盐，负责细胞内蛋白质的硝化。血管过氧亚硝酸盐与肝细胞过氧亚硝酸盐形成和肝损伤的病理生理学相关性仍有待确定。
Peroxynitrite may be involved in acetaminophen-induced liver damage. However, it is unclear if peroxynitrite is generated in hepatocytes or in the vasculature. To address this question, we treated C3Heb/FeJ mice with 300 mg/kg acetaminophen and assessed nitrotyrosine protein adducts as indicator for peroxynitrite formation. Vascular nitrotyrosine staining was evident before liver injury between 0.5 and 2 h after acetaminophen treatment. However, liver injury developed parallel to hepatocellular nitrotyrosine staining between 2 and 6 h after acetaminophen. The mitochondrial content of glutathione disulfide, as indicator of reactive oxygen formation determined 6 h after acetaminophen, increased from 2.8 +/- 0.6% in controls to 23.5 +/- 5.1%. A high dose of allopurinol (100 mg/kg) strongly attenuated acetaminophen protein-adduct formation and prevented the mitochondrial oxidant stress and liver injury after acetaminophen. Lower doses of allopurinol, which are equally effective in inhibiting xanthine oxidase, were not protective and had no effect on nitrotyrosine staining and acetaminophen protein adduct formation. In vitro experiments showed that allopurinol is not a direct scavenger of peroxynitrite. We conclude that there is vascular peroxynitrite formation during the first 2 h after acetaminophen treatment. On the other hand, reactive metabolites of acetaminophen bind to intracellular proteins and cause mitochondrial dysfunction and superoxide formation. Mitochondrial superoxide reacts with nitric oxide to form peroxynitrite, which is responsible for intracellular protein nitration. The pathophysiological relevance of vascular peroxynitrite for hepatocellular peroxynitrite formation and liver injury remains to be established.