The Oxygen Tension Modulates Acetaminophen-Induced Mitochondrial Oxidant Stress and Cell Injury in Cultured Hepatocytes
The Oxygen Tension Modulates Acetaminophen-Induced Mitochondrial Oxidant Stress and Cell Injury in Cultured Hepatocytes
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DOI：
10.1093/toxsci/kfq208
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发表时间：
2010-10-01
影响因子：
3.8
通讯作者：
Jaeschke, Hartmut
中科院分区：
文献类型：
--
作者：
Yan, Hui-Min;Ramachandran, Anup;Jaeschke, Hartmut
氧化应激和线粒体功能障碍在对乙酰氨基酚（APAP）诱导的肝细胞死亡中起重要作用。然而，在这个过程中涉及的确切机制是有争议的，部分原因是在体外和体内研究之间的结果的差异。在这种情况下，一个主要的区别是氧张力，培养中的细胞暴露于21%的氧气，而肝脏中的细胞经历从3%到9%的氧气梯度。为了确定氧分压是否可以调节肝细胞对APAP的反应，在各种氧分压和线粒体功能障碍下用5 mM APAP处理原代小鼠肝细胞长达15小时（2，3-bis[2-methoxy-4-硝基-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt assay，5，5'，6，6'-tetrachloro-1，1，3，3-四乙基苯并咪唑基羰花青碘化物[JC-1]荧光比率）和细胞死亡（乳酸脱氢酶释放）进行评价。线粒体活性氧和活性氮分别用线粒体红或二氢罗丹明荧光和硝基酪氨酸染色。将肝细胞暴露于21%O-2的5 mM APAP中，导致线粒体氧化应激形成，线粒体功能恶化，早在6 h就出现膜电位丧失，15 h出现大量细胞死亡。细胞在10%O-2下培养6 h后，线粒体氧化应激没有增加，线粒体功能得到更好的保护，并在15 h时显着防止细胞死亡。此外，二氢罗丹明荧光显着衰减在10%的氧气。在5%氧气下培养的细胞也受到保护，但显示出缺氧的证据（乳酸盐积累和缺氧诱导因子-1 α的核转位）。这些结果表明，氧张力可以调节肝细胞对APAP的反应，低生理水平（10%）降低线粒体氧化应激和延迟肝细胞死亡。
Oxidative stress and mitochondrial dysfunction play an important role in acetaminophen (APAP)-induced hepatocyte cell death. However, exact mechanisms involved in the process are controversial, in part, because of the disparity in findings between in vitro and in vivo studies. A major difference in this context is the oxygen tension, with cells in culture being exposed to 21% oxygen, whereas those in the liver experience a gradient from 3 to 9% oxygen. To determine if oxygen tensions could modulate hepatocyte responses to APAP, primary mouse hepatocytes were treated with 5mM APAP for up to 15 h under various oxygen tensions and mitochondrial dysfunction (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt assay, 5,5',6,6'-tetrachloro-1,1,3,3-tetraethylbenzimidazolylcarbocyanine iodide [JC-1] fluorescence ratio) and cell death (lactate dehydrogenase release) was evaluated. Mitochondrial reactive oxygen and reactive nitrogen species were measured using Mitosox Red or dihydrorhodamine fluorescence and nitrotyrosine staining, respectively. Exposure of hepatocytes to 5mM APAP at 21% O-2 resulted in mitochondrial oxidant stress formation, deterioration of mitochondrial function, and loss of membrane potential as early as 6 h and massive cell death at 15 h. Culture of cells at 10% O-2 resulted in no increase in mitochondrial oxidant stress and better preserved mitochondrial function at 6 h and significant protection against cell death at 15 h. Furthermore, dihydrorhodamine fluorescence was significantly attenuated at 10% oxygen. Cells cultured at 5% oxygen were also protected but showed evidence of hypoxia (accumulation of lactate and nuclear translocation of hypoxia-inducing factor-1 alpha). These results suggest that oxygen tension can modulate hepatocyte responses to APAP, with low physiological levels (10%) decreasing mitochondrial oxidant stress and delaying hepatocyte cell death.