Kon Kazuyoshi, Ikejima Kenichi, Okumura Kyoko, Aoyama Tomonori, Arai Kumiko, Takei Yoshiyuki, Lemasters John J, Sato Nobuhiro
Department of Gastroenterology, Juntendo University School of Medicine, Tokyo, Japan.
J Gastroenterol Hepatol. 2007 Jun;22 Suppl 1:S49-52. doi: 10.1111/j.1440-1746.2007.04962.x.
Acetaminophen overdose causes liver injury by mechanisms involving glutathione depletion, oxidative stress and mitochondrial dysfunction. The role of apoptosis in acetaminophen-induced cell killing is still controversial. Here, our aim was to evaluate the mitochondrial permeability transition (MPT) as a key factor in acetaminophen-induced necrotic and apoptotic killing of primary cultured mouse hepatocytes. Acetaminophen (10 micromol/L) induced necrotic killing in approximately 50% of hepatocytes after 6 h and cyclosporin A (CsA), MPT inhibitor, temporarily decreased necrotic killing after 6 h, but cytoprotection was lost after 16 h. Confocal microscopy revealed mitochondrial depolarization and inner membrane permeabilization at approximately 4.5 h after acetaminophen. CsA delayed these changes indicative of the MPT to about 11 h after acetaminophen. TUNEL labeling and caspase 3 activation also increased after acetaminophen. Fructose (20 mmol/L, an ATP-generating glycolytic substrate) plus glycine (5 mmol/L, a membrane stabilizing amino acid) prevented nearly all necrotic cell killing but paradoxically increased apoptosis. In conclusion, acetaminophen induces the MPT and ATP-depletion-dependent necrosis or caspase-dependent apoptosis as determined, in part, by ATP availability from glycolysis.
对乙酰氨基酚过量通过涉及谷胱甘肽耗竭、氧化应激和线粒体功能障碍的机制导致肝损伤。细胞凋亡在对乙酰氨基酚诱导的细胞杀伤中的作用仍存在争议。在此，我们的目的是评估线粒体通透性转换（MPT）作为对乙酰氨基酚诱导原代培养小鼠肝细胞坏死和凋亡性杀伤的关键因素。对乙酰氨基酚（10微摩尔/升）在6小时后诱导约50%的肝细胞发生坏死性杀伤，而MPT抑制剂环孢素A（CsA）在6小时后暂时减少了坏死性杀伤，但在16小时后细胞保护作用丧失。共聚焦显微镜显示，对乙酰氨基酚作用后约4.5小时出现线粒体去极化和内膜通透性增加。CsA将这些表明MPT的变化延迟至对乙酰氨基酚作用后约11小时。对乙酰氨基酚作用后TUNEL标记和半胱天冬酶3激活也增加。果糖（20毫摩尔/升，一种产生ATP的糖酵解底物）加甘氨酸（5毫摩尔/升，一种稳定膜的氨基酸）几乎阻止了所有坏死性细胞杀伤，但反常地增加了细胞凋亡。总之，对乙酰氨基酚诱导MPT以及ATP耗竭依赖性坏死或半胱天冬酶依赖性凋亡，这部分取决于糖酵解产生的ATP可用性。
