INTRACELLULAR PH DURING CHEMICAL HYPOXIA IN CULTURED RAT HEPATOCYTES - PROTECTION BY INTRACELLULAR ACIDOSIS AGAINST THE ONSET OF CELL-DEATH
INTRACELLULAR PH DURING CHEMICAL HYPOXIA IN CULTURED RAT HEPATOCYTES - PROTECTION BY INTRACELLULAR ACIDOSIS AGAINST THE ONSET OF CELL-DEATH
复制标题
DOI：
10.1172/jci113896
复制
发表时间：
1989-02-01
影响因子：
15.9
通讯作者：
LEMASTERS, JJ
中科院分区：
文献类型：
--
作者：
GORES, GJ;NIEMINEN, AL;LEMASTERS, JJ
在培养的大鼠肝细胞中，通过KCN和碘乙酸盐（化学缺氧）代谢抑制ATP耗竭后，评价细胞外pH（pH 0）、细胞内pH（pHi）和细胞活力丧失之间的关系。使用多参数数字化视频显微镜，通过2“，7”-双羧乙基-5，6-羧基荧光素（BCECF）荧光的比率成像，在单细胞中测量pHi。在pHo为7.4的化学缺氧过程中，pHi在10分钟内从7.36下降到6.33，pHi在6.1-6.5之间维持30-40分钟（平台期）。此后，pHi开始上升，细胞死亡，随后在几分钟内，证明了核染色碘化丙啶和BCECF从细胞质的同时泄漏。酸性pH 0产生的pHi稍大的下降，延长了细胞内酸中毒的平台期，并延迟了细胞死亡的发生。抑制Na+/H+交换也延长了平台期和延迟细胞死亡。与此相反，莫能菌素或取代葡萄糖酸盐的Cl-在缓冲液中含有HCO 3-废除跨质膜的pH梯度和缩短细胞存活。结果表明，ATP耗竭后的细胞内酸中毒延迟了细胞死亡的发生，而酸中毒程度的降低加速了细胞杀伤。我们的结论是，细胞内酸中毒保护肝细胞死亡ATP耗竭，一种现象，可能是一种保护性适应缺氧和缺血性应激。
The relationships between extracellular pH (pH0), intracellular pH (pHi), and loss of cell viability were evaluated in cultured rat hepatocytes after ATP depletion by metabolic inhibition with KCN and iodoacetate (chemical hypoxia). pHi was measured in single cells by ratio imaging of 2'',7''-biscarboxyethyl-5,6-carboxyfluorescein (BCECF) fluorescence using multiparameter digitized video microscopy. During chemical hypoxia at pHo of 7.4, pHi decreased from 7.36 to 6.33 within 10 min. pHi remained at 6.1-6.5 for 30-40 min (plateau phase). Thereafter, pHi began to rise and cell death ensued within minutes, as evidenced by nuclear staining with propidium iodide and coincident leakage of BCECF from the cytoplasm. An acidic pH0 produced a slightly greater drop in pHi, prolonged the plateau phase of intracellular acidosis, and delayed the onset of cell death. Inhibition of Na+/H+ exchange also prolonged the plateau phase and delayed cell death. In contrast, monensin or substitution of gluconate for Cl- in buffer containing HCO3- abolished the pH gradient across the plasma membrane and shortened cell survival. The results indicate that intracellular acidosis after ATP depletion delays the onset of cell death, whereas reduction of the degree of acidosis accelerates cell killing. We conclude that intracellular acidosis protects against hepatocellular death from ATP depletion, a phenomenon that may represent a protective adaptation against hypoxic and ischemic stress.