Herman B, Gores G J, Nieminen A L, Kawanishi T, Harman A, Lemasters J J
Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599.
Crit Rev Toxicol. 1990;21(2):127-48. doi: 10.3109/10408449009089876.
The critical events that lead to the transition from reversible to irreversible injury remain unclear. Studies are reviewed that have suggested that a rise in cytosolic free Ca2+ initiates plasma membrane bleb formation and a sequence of events that leads ultimately to cell death. In recent studies, we have measured changes in cytosolic free Ca2+, mitochondrial membrane potential, cytosolic pH, and cell surface blebbing in relation to the onset of irreversible injury and cell death following anoxic and toxic injury to single hepatocytes utilizing multiparameter digitized video microscopy (MDVM). MDVM is an emerging new technology that permits single living cells to be labeled with multiple probes whose fluorescence is responsive to specific cellular parameters of interest. Fluorescence images specific for each probe are collected over time, and then digitized and stored. Image analysis and processing then permits quantitation of the spatial distribution of the various parameters within the single living cells. Our results indicate the following: (1) formation of plasma membrane blebs accompanies all types of injury in hepatocytes; (2) cell death is a rapid event, initiated by rupture of a plasma membrane bleb, and is coincident with the onset of irreversible injury; (3) an increase of cytosolic free Ca2+ is not the stimulus for bleb formation or the final common pathway leading to cell death; (4) a decrease of mitochondrial membrane potential precedes loss of cell viability; (5) cytosolic pH falls by more than 1 pH unit during chemical hypoxia. This acidosis protects against the onset of cell death.
导致从可逆性损伤转变为不可逆性损伤的关键事件仍不清楚。本文回顾了一些研究，这些研究表明胞质游离Ca2+的升高会引发质膜泡形成以及一系列最终导致细胞死亡的事件。在最近的研究中，我们利用多参数数字化视频显微镜（MDVM），测量了单个肝细胞在缺氧和毒性损伤后，胞质游离Ca2+、线粒体膜电位、胞质pH值以及细胞表面泡化与不可逆损伤和细胞死亡发生之间的变化关系。MDVM是一项新兴的新技术，它允许用多种对特定感兴趣的细胞参数有荧光反应的探针标记单个活细胞。随着时间的推移收集每个探针特有的荧光图像，然后进行数字化存储。图像分析和处理随后允许对单个活细胞内各种参数的空间分布进行定量分析。我们的结果表明：（1）质膜泡的形成伴随着肝细胞的所有类型损伤；（2）细胞死亡是一个快速事件，由质膜泡破裂引发，且与不可逆损伤的发生同时出现；（3）胞质游离Ca2+的增加不是泡形成的刺激因素或导致细胞死亡的最终共同途径；（4）线粒体膜电位的降低先于细胞活力的丧失；（5）在化学性缺氧期间，胞质pH值下降超过1个pH单位。这种酸中毒可防止细胞死亡的发生。
