Apoptosis is prevented by administration of superoxide dismutase in dogs with reperfused myocardial infarction
Apoptosis is prevented by administration of superoxide dismutase in dogs with reperfused myocardial infarction
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DOI：
10.1007/s003950050068
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发表时间：
1998-04-01
影响因子：
9.5
通讯作者：
Becker, LC
中科院分区：
文献类型：
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作者：
Ambrosio, G;Zweier, JL;Becker, LC
缺血期间的血流相似。此外，仅在复流时给予治疗。因此，细胞死亡程度的降低可能是预防与回流时氧自由基产生相关的事件的结果。在研究时，没有迹象表明细胞凋亡可以显著促进心肌细胞死亡。然而，最近我们重新分析了该研究的组织标本，以研究两组之间的细胞凋亡程度是否不同（2）。将每只犬梗死区域的福尔马林固定、石蜡包埋组织块切成5 µm厚切片。对切片进行处理，以检测DNA链断裂产生的特定寡核苷酸序列，如“TUNEL”反应（末端转移酶dUTP缺口末端标记）所证明（18）。该染色技术允许检测原位组织样本中细胞凋亡特异性的核DNA片段化产物（9，11）。与基于识别典型DNA“梯状”的电泳方法相比，该技术不需要组织破坏，并且其允许正确鉴定显示DNA片段化的细胞类型。使用再流后48小时的组织切片提供了细胞死亡过程完全和中性粒细胞浸润早已消失的优势。显微镜图像由经验丰富的研究人员分析，不知道治疗分配，细胞凋亡的程度表示在0至5半定量评分。在每只对照犬中，在再灌注区的肌细胞核中观察到广泛程度的阳性染色（图1A）。相比之下，SOD处理犬的一半组织标本缺乏TUNEL染色阳性（图1B），其余切片中存在中度染色。总体而言，这导致SOD处理犬的细胞凋亡程度显著较小（图2）。
flow during ischemia were similar. Furthermore, treatment was only administered at the time of reflow. Thus, reduction in the extent of cell death was likely the result of prevention of events linked to oxygen radical production at reflow. At the time of the study, there was no hint that apoptosis could significantly contribute to myocardial cell death. However, more recently we have reanalyzed tissue specimens from that study to investigate whether extent of apoptosis was different between the two groups (2). Formalin-fixed, paraffin-embedded tissue blocks from the infarcted area of each dog were cut into 5 µm thick sections. Sections were processed to detect occurrence of specific oligonucleotide sequenses from DNA strand breaks, as evidenced by the “TUNEL” reaction (terminal transferase dUTP Nick-End Labeling)(18). This staining technique allows detection of nuclear DNA fragmentation products specific for apoptosis in in situ tissue specimens (9, 11). Compared to the electrophoretic method based on recognition of the typical DNA “laddering”, this technique does not require tissue disruption, and it allows proper identification of the cell types which show DNA fragmentation. Use of tissue sections taken 48 hours after reflow afforded the advantages that the process of cell death was complete and that neutrophil infiltration was long gone. Microscopic images were analyzed by experienced investigators unaware of treatment allocation, and the extent of apoptosis was expressed on a 0 to 5 semiquantitative score. In each control dog an extensive degree of positive stain was observed in the nuclei of myocytes from the reperfused area (Fig. 1A). In contrast, half of the tissue specimens from SOD treated dogs lacked positivity for TUNEL staining (Fig. 1B) with moderate stain present in the remaining sections. Overall, this resulted in a significantly smaller extent of apoptosis in SOD treated dogs (Fig. 2).