EXTRACELLULAR ACIDOSIS DELAYS ONSET OF CELL-DEATH IN ATP-DEPLETED HEPATOCYTES
EXTRACELLULAR ACIDOSIS DELAYS ONSET OF CELL-DEATH IN ATP-DEPLETED HEPATOCYTES
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DOI：
10.1152/ajpcell.1988.255.3.c315
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发表时间：
1988-09-01
影响因子：
--
通讯作者：
LEMASTERS, JJ
中科院分区：
文献类型：
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作者：
GORES, GJ;NIEMINEN, AL;LEMASTERS, JJ
使用碘化丙啶总荧光的荧光测定法用于连续定量肝细胞悬液中的细胞活力。对于暴露于KCN的活肝细胞，荧光与乳酸脱氢酶释放和碘化丙啶核标记成线性比例。在KCN处理的肝细胞中，碘乙酸消除了进食状态和果糖对细胞死亡的保护作用。用KCN和碘乙酸建立了一种细胞死亡模型，以模拟缺氧的ATP耗竭。这种“化学缺氧”被用来研究pH在细胞死亡中的作用。在pH 7.4时，细胞活力在120分钟后下降至10%，而在pH 5.5-7.0时，细胞活力为65- 85%，几乎与含氧量正常的细胞相同。在酸中毒条件下的化学缺氧期间，pH值恢复到7.4导致细胞杀死的快速加速，这是一个“pH悖论”。抑制Na+-H+交换增加了存活率，而促进细胞内Cl-与细胞外HCO 3-的交换增强了细胞杀伤。莫能菌素，Na+-H+离子载体，在pH 7.4下增强细胞杀伤，但在pH 6.2下不增强。结果表明，细胞外酸中毒显着保护ATP耗竭后的细胞杀伤，通过细胞质酸化介导的效果出现。
A fluorometric assay using propidium iodide total fluorescence was utilized to quantitate cell viability in hepatocyte suspensions continuously. For viable hepatocytes exposed to KCN, fluorescence was linearly proportional to lactate dehydrogenase release and to nuclear labeling by propidium iodide. In KCN-treated hepatocytes, iodoacetate eliminated the protective effect of the fed state and fructose against the onset of cell death. A model of cell death with KCN and iodoacetate was developed to mimic the ATP depletion of anoxia. This "chemical hypoxia" was used to investigate the role of pH in cell death. At pH 7.4, cell viability decreased to 10% after 120 min, whereas at pH 5.5-7.0, cell viability was 65-85%, nearly the same as normoxic cells. During chemical hypoxia under acidotic conditions, a return to pH to 7.4 resulted in a rapid acceleration of cell killing, a "pH paradox." Inhibition of Na+-H+ enchange increased survival, whereas promoting exchange of intracellular Cl- for extracellular HCO3- potentiated cell killing. Monensin, a Na+-H+ ionophore, potentiated cell killing at pH 7.4 but not at pH 6.2. The results show that extracellular acidosis markedly protects against cell killing after ATP depletion, an effect that appears mediated through cytoplasmic acidification.