Pathophysiological study of arrhythmogenesis in ischemic heart

缺血性心脏心律失常发生的病理生理学研究

• 批准号: 14370081
• 负责人: TAKAMATSU Tetsuro
• 金额: $ 7.23万
• 依托单位: Kyoto Prefectural University of Medicine
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14370081/
• 关键词: Myocardial infarction; Calcium ion; Gap junction; Arrhythmia; Real-time confocal microscope

To know how abnormal intracellular Ca^<2+> dynamics and gap junctional communication are integrated into arrhythmia, we visualized the intracellular Ca^<2+> dynamics by in situ Ca^<2+> imaging and expression of connexin 43 by GFP technique in ischemic rat hearts. Based on the hypothesis that Ca^<2+> waves would arise at the border zone of the infarction as a consequence of Ca^<2+> overload, we conducted in situ Ca^<2+> imaging. The subepicardial myocytes at the border zone showed abnormal intracellular calcium handling and gap junctional intercellular communication, such as stimulation-induced Ca^<2+> waves, which were evoked exclusively on electrical stimulation, instead of Ca^<2+> transients. These abnormal [Ca^<2+>]_i dynamics are supposed to be an important substrate for arrhythmias in ischemic hearts. We also made an EBV-based plasmid encoding connexin43-mRFP fusion protein for elucidating effects of abnormal gap junctional communication on ventricular conductivity. The EBV-based plasmid has different fluorescent wavelength spectrum from that of a calcium indicator, fluo-3,and were infused into the aortic root of rats. To maximize delivery, the aortic root was transiently occluded during a brief asystole. We concluded that these techniques could substantially contribute to our understanding of relationship between intracellular Ca^<2+> dynamics and expression of connexin 43 in ischemic rat hearts.

为了解细胞内钙离子动力学异常和缝隙连接通讯功能异常与心律失常的关系，我们用原位钙离子成像技术观察了缺血大鼠心肌细胞内钙离子动力学变化，并用绿色荧光蛋白(GFP)技术检测了细胞间隙连接蛋白43的表达。基于假设由于钙超载，在梗塞边缘区域会出现钙波，我们进行了原位钙波成像。交界区的心外膜下心肌细胞表现出异常的细胞内钙通道和缝隙连接通讯，如刺激诱导的Ca^&lt；2+&gt；波只在电刺激时诱发，而不是Ca^&lt；2+&gt；；这些异常的[Ca~(2+)]_i动力学被认为是缺血心脏心律失常的重要底物。我们还制作了基于EBV的编码连接蛋白43-MRFP融合蛋白的质粒，以阐明缝隙连接通讯异常对心室电导的影响。以EBV为基础的质粒具有与钙指示剂Fluo-3不同的荧光波长，并将其注入大鼠的主动脉根部。为了最大限度地输送，在短暂的心搏停止期间，主动脉根部被暂时闭塞。我们的结论是，这些技术可以帮助我们理解缺血大鼠心脏细胞内钙动力学和连接蛋白43表达之间的关系。

项目成果

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Naito, A.: "Early stage-specific inhibitors of cardiomyocyte differentiation and expression of Osx/Nkx-2.5 and GATA-4 by phosphatidylinositol 3-kinase inhibitor LY294002"Exp Cell Res. 291. 56-69 (2003)

Naito, A.：“磷脂酰肌醇 3-激酶抑制剂 LY294002 对心肌细胞分化和 Osx/Nkx-2.5 和 GATA-4 表达的早期特异性抑制剂”Exp Cell Res。

Naito A: "Early stage-specific inhibitors of cardiomyocyte differentiation and expression of Csx/Nkx-2.5 and GATA-4 by phosphatidylinositol 3-kinase inhibitor LY294002."Exp Cell Res. 291. 56-69 (2003)

Naito A：“磷脂酰肌醇 3-激酶抑制剂 LY294002 对心肌细胞分化和 Csx/Nkx-2.5 和 GATA-4 表达的早期特异性抑制剂。”Exp Cell Res。