Linnik M D, Miller J A, Sprinkle-Cavallo J, Mason P J, Thompson F Y, Montgomery L R, Schroeder K K
Marion Merrell Dow Research Institute, Cincinnati, OH 45215-6300, USA.
Brain Res Mol Brain Res. 1995 Aug;32(1):116-24. doi: 10.1016/0169-328x(95)00069-5.
Recent investigations have demonstrated internucleosomal DNA fragmentation in ischemic neuronal tissue. This type of fragmentation is characteristic of programmed cell death or apoptosis and suggests that neuronal death in stroke may be more complex than simple necrotic death. The present experiments provide a detailed examination of the regional localization and time course for apoptotic DNA fragmentation in the cerebral cortex following focal cerebral ischemia. Spontaneously hypertensive rats were subjected to permanent right middle cerebral artery occlusion and the cerebral cortices were examined for evidence of DNA fragmentation using electrophoretic, flow cytometric, and histological approaches. An electrophoretic examination of cortical DNA at 24 h after the occlusion indicated that the majority of nucleosomal ladders were in the transition zone or penumbra and the core of the infarction, with no fragmentation apparent in the contralateral normal cortex. A flow cytometric analysis of DNA fragmentation in intact cells revealed a similar pattern, with increased fragmentation observed in ischemic cortex vs. the contralateral cortex. Saggital sections taken 1.5 mm lateral to midline were collected from animals at 1, 4, and 24 h after the infarction and DNA fragmentation was examined histologically by terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL) staining. Quantitative analysis of these sections indicated that DNA fragmentation can be observed in the anterior and central area of the infarctions as soon as 1 h after the occlusion and that the extent and magnitude of the fragmentation increases at 4 and 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)
近期研究已证实在缺血性神经组织中存在核小体间DNA片段化。这种片段化类型是程序性细胞死亡或凋亡的特征，提示中风时神经元死亡可能比单纯坏死性死亡更为复杂。本实验对局灶性脑缺血后大脑皮质凋亡性DNA片段化的区域定位和时间进程进行了详细研究。对自发性高血压大鼠实施永久性右侧大脑中动脉闭塞，然后采用电泳、流式细胞术和组织学方法检查大脑皮质，以寻找DNA片段化的证据。闭塞后24小时对皮质DNA进行的电泳检查表明，大多数核小体梯带位于梗死灶的过渡区或半暗带以及梗死核心区，而对侧正常皮质未见明显片段化。对完整细胞中DNA片段化的流式细胞术分析显示了类似的模式，与对侧皮质相比，缺血皮质中观察到片段化增加。在梗死后1、4和24小时从动物身上采集距中线外侧1.5毫米处的矢状切片，通过末端脱氧核苷酸转移酶介导的dUTP生物素缺口末端标记（TUNEL）染色对DNA片段化进行组织学检查。对这些切片的定量分析表明，闭塞后1小时即可在梗死灶的前部和中央区域观察到DNA片段化，且在4小时和24小时时片段化的程度和幅度增加。（摘要截于250字）
