Apoptotic and necrotic death mechanisms are concomitantly activated in the same cell after cerebral ischemia
Apoptotic and necrotic death mechanisms are concomitantly activated in the same cell after cerebral ischemia
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DOI：
10.1161/01.str.0000136149.81831.c5
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发表时间：
2004-09-01
期刊：
影响因子：
8.3
通讯作者：
Dalkara, T
中科院分区：
文献类型：
--
作者：
Ünal-Çevik, I;Kilinç, M;Dalkara, T
背景和目的-脑缺血后坏死和凋亡细胞死亡机制都被激活.然而，它们是否在同一细胞中或在离散的细胞群体中同时活跃尚不清楚。方法-我们研究了在短暂或永久性局灶性缺血小鼠脑中细胞水平上两种途径的激活。结果-缺血后4小时，弥漫性组织蛋白酶-B溢出进入细胞质，表明溶酶体渗漏，在对活性形式的caspase-3（p20）免疫反应的神经元内观察到。用半胱天冬酶切割的肌动蛋白片段共标记质膜渗漏的缺血神经元（碘化丙啶阳性），并显示具有凋亡形态的TUNEL阳性细胞核。在72小时，高达27%的具有半胱天冬酶活性的细胞显示出提示继发性necross.Conclusions的形态学特征-这些数据表明，早期和同时增加的半胱天冬酶-3和组织蛋白酶-B的活动，随后出现半胱天冬酶裂解产物，DNA片段化，和膜崩解，提示坏死和凋亡细胞死亡的子程序在缺血性神经元中伴随激活，并且主导细胞死亡表型由每个过程的相对速度决定。
Background and Purpose - Both necrotic and apoptotic cell death mechanisms are activated after cerebral ischemia. However, whether they are concomitantly active in the same cell or in discrete cell populations is not known.Methods - We investigated activation of both pathways at the cellular level in mice brains subjected to transient or permanent focal ischemia.Results - Four hours after ischemia, diffuse cathepsin-B spillage into cytoplasm, suggesting lysosomal leakage, was observed within neurons immunoreactive for the active form of caspase-3 (p20). Ischemic neurons with a leaky plasma membrane ( positive for propidium iodide) were colabeled with caspase-cleaved actin fragment and exhibited TUNEL-positive nuclei having apoptotic morphology. At 72 hours, up to 27% of cells with caspase activity displayed morphological features suggestive of secondary necrosis.Conclusions - These data, demonstrating an early and concurrent increase in caspase-3 and cathepsin-B activities followed by appearance of caspase-cleavage products, DNA fragmentation, and membrane disintegration, suggest that subroutines of necrotic and apoptotic cell death are concomitantly activated in ischemic neurons and that the dominant cell death phenotype is determined by the relative speed of each process.