The Study on the Mechanism of Ischemic Preconditioning of the Myocardium

心肌缺血预适应机制的研究

• 批准号: 09670738
• 负责人: BABA Akira
• 金额: $ 2.37万
• 依托单位: Wakayama Medical College
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09670738/
• 关键词: ischemic preconditioning; hypoxia-reperfusion injury; ATP-sensitive K channel; mitochondria; diazoxide; intracellular hydrogen concentration; 虚血・再灌流障害; 虚血・再潅流障害; 細胞内Ca; Na,Ca交換機構

ATP-sensitive K channel (KィイD2ATPィエD2 channel) have been reported to play a major role in ischemic preconditioning. The present study was designed to clarify the effect of mitochondrial KィイD2ATPィエD2 channel opener on the hypoxia-reperfusion injury. Ventricular myocytes isolated from Sprague-Dawley rat were studied. Cardiomyocytes were superfused with anoxic glucose-free Tyrode solution, which was equilibrated with 99.99% nitrogen under positive pressure, for 15 minutes followed by normoxic Tyrode solution for 40 minutes. Diazoxide (30 μM), a specific mitochondrial KィイD2ATPィエD2 channel opener was administered to the diazoxide group (D group) 5 minutes prior to anoxic perfusion until the end of anoxic perfusion. Intracellular pH measured by BCECF and the shape of myocytes were recorded by microscopic fluorometric system ARGUS 200 (Hamamatsu Photonics, Hamamatsu, Japan). Rod-shaped cell was considered to be alive. The viability of cardiomyocytes at the end of anoxia-reoxygenation perfusion was significantly higher in D group compared with control group (59.3±10.6 vs 22.0±13.3% ; n=8,6 rats ; <0.05). The pH of myocytes was similar between two groups at the end of anoxic perfusion. Most of the killed cells of the control group showed round cells but the half of the killed cell of D group showed rigor contracture (control group : round cells 62.3%, rigor contracture 10.7% ; D group : round cells 20.3%, rigor contracture 19.5%). When isolated cardiomyocytes were made skinned by saponin after washing by EGTA-containing solution, and suspended in ATP-depleted solution, myocytes became rigor contracture. Mitochondrial KィイD2ATPィエD2 channel opener showed the protective effect on the anoxia-reoxygenation injury of the isolated cardiomyocyte of rat without any change of intracellular pH. This protective effect might be due to reducing Ca overload during anoxia-reoxygenation perfusion.

据报道，ATP 敏感 K 通道（KiiD2ATPieD2 通道）在缺血预处理中发挥重要作用。本研究旨在阐明线粒体 KiiD2ATPieD2 通道开放剂对分离自 Sprague-Dawley 大鼠的心室肌细胞的影响。研究人员用缺氧的无葡萄糖 Tyrode 溶液灌注心肌细胞，并用 平衡。正压下 99.99% 氮气 15 分钟，然后在缺氧灌注前 5 分钟向二氮嗪组（D 组）施用二氮嗪（30 μM）（一种特定的线粒体关键 D2ATP 通道开放剂）40 分钟，直至缺氧灌注。缺氧灌注结束时，通过 BCECF 测量细胞内 pH 值，并通过显微荧光系统 ARGUS 记录心肌细胞的形状。 200（Hamamatsu Photonics，Hamamatsu，日本）认为缺氧复氧灌注结束时心肌细胞的活力显着高于对照组（59.3±10.6 vs 22.0±13.3）。 % ; n=8,6 只大鼠; <0.05) 缺氧灌注结束时两组之间的肌细胞 pH 值相似。对照组灭活细胞中有一半呈圆形细胞，但D组一半灭活细胞呈僵硬挛缩（对照组：圆形细胞62.3％，僵硬挛缩10.7％；D组：圆形细胞20.3％，僵硬挛缩19.5％当分离的心肌细胞用含有EGTA的溶液洗涤后用皂苷去皮，并悬浮在ATP耗尽的溶液中时，心肌细胞变成线粒体KeyD2ATPD2通道开放剂对大鼠离体心肌细胞的缺氧复氧损伤具有保护作用，而细胞内pH没有任何变化，这种保护作用可能是由于减少缺氧复氧灌注过程中的Ca过载。

项目成果

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Shiotani M、Kawabe T、Hano T、Baba A 等人：“尼卡地平减轻了离体微灌注兔子传入动脉的缺血/再灌注损伤”高血压杂志。

Shiotani M., Kawabe T., Hano T., Baba A., et al.: "Nicardipine diminished ischemia/reperfusion injury on isolated microperfused rabbeit afferent arter arterioles."Journal of Hypertension. 16 (suppl2). S84 (1998)

Shiotani M.、Kawabe T.、Hano T.、Baba A. 等人：“尼卡地平可减轻离体微灌注兔传入动脉小动脉的缺血/再灌注损伤。”高血压杂志。

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