Lemasters J J, Gores G J, Nieminen A L, Dawson T L, Wray B E, Herman B
Department of Cell Biology and Anatomy, School of Medicine, University of North Carolina, Chapel Hill 27599.
Environ Health Perspect. 1990 Mar;84:83-94. doi: 10.1289/ehp.908483.
There is no clear picture of the critical events that lead to the transition from reversible to irreversible injury. Many studies have suggested that a rise in cytosolic free Ca2+ initiates plasma membrane bleb formation and a sequence of events that lead 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 by using 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, digitized, and stored. Image analysis and processing then permits quantitation of the spatial distribution of the various parameters with the single living cells. Our results indicate the following: The formation of plasma membrane blebs accompanies all types of injury in hepatocytes. Cell death is a rapid event initiated by rupture of a plasma membrane bleb, and it is coincident with the onset of irreversible injury. An increase of cytosolic free Ca2+ is not the stimulus for bleb formation or the final common pathway leading to cell death. A decrease of mitochondrial membrane potential precedes the loss of cell viability. 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尚无清晰的图景。许多研究表明，胞质游离Ca2+浓度升高会引发质膜气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，我们使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值以及细胞表面气泡形成与不可逆损伤和细胞死亡发生之间的变化。MDVM是一项新兴技术，它允许用多种对特定感兴趣的细胞参数有荧光响应的探针标记单个活细胞。随时间收集针对每个探针的荧光图像，进行数字化并存储。然后通过图像分析和处理对单个活细胞中各种参数的空间分布进行定量。我们的结果表明：质膜气泡形成伴随肝细胞的所有类型损伤。细胞死亡是由质膜气泡破裂引发的快速事件，且与不可逆损伤的发生同时出现。胞质游离Ca2+升高并非气泡形成的刺激因素，也不是导致细胞死亡的最终共同途径。线粒体膜电位降低先于细胞活力丧失。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。
