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Analysis of ischaemia in micro-myocardial region : evaluation of micro-deformation and image of NADH metabolic activity during ischaemia in a beating heart

微心肌区域缺血分析：跳动心脏缺血时微变形评估和 NADH 代谢活性图像

基本信息

批准号：
11558115
负责人：
OGASAWARA Yasuo
金额：
$ 8.51万
依托单位：
Kawasaki Medical School
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11558115/
关键词：
microstrain NADH ischemia coronary microcirculation high speed CCD microscope マクロストレイン

项目摘要

The major size of a vascular bed that a minimum arteriole governs within myocardium is several hundreds mm long. At this level of size, the heterogeneity of coronary blood-flow distribution is remarkable. However, it is unknown whether the heterogeneity of a coronary blood-flow distribution relates to the myocardial micro-deformation in a beating heart.We have recently developed a micro-light markers implantation method onto the cardiac surface of anaesthetized open-chest dogs and directly observed the myocardial micro-deformation in hundreds micrometer order using our newly developed high-magnified(×200), high-speed(200 frames/sec)CCD intravaital videomicroscope. In comparison with this, deformation of larger scale(millimeter order sample size)was also analyzed using an intra-vital microscope with lower magnification(×50). Although the myocardial deformation by cardiac contraction in a macrodomain was comparatively uniform, deformation in a micro-domain showed heterogeneity.In addition, measurement and analysis of oxygen metabolism image of the isolated rat heart were done using a NADH fluorescence method. The average size of the heterogeneous myocardial deformation unit and patchy NADH fluorescence unit betraying mayocardial oxygen metabolism were in the same order. Furthermore, trasitional NADH activity at myocardial wall section was observed between epimyocardium and endomyocardium. The time constant of appearance and disappearance of NADH fluorescence revealed that endomyocardium is much more vulnerable to hypoxia than epimyocardium.

心肌内由最小微动脉支配的血管床的主要尺寸为数百mm长。在这个尺寸水平上，冠状动脉血流分布的不均匀性是显著的。本实验室在麻醉开胸犬心脏表面植入微光标记物，利用自行研制的高倍放大（×200），高速（200帧/秒）CCD阴道内视频显微镜。与此相比，还使用放大倍数较低（×50）的活体显微镜分析了较大尺度（毫米级样品尺寸）的变形。心肌收缩引起的心肌变形在宏观上比较均匀，但在微观上表现出不均匀性。此外，采用NADH荧光法对离体大鼠心脏的氧代谢图像进行了测量和分析。心肌变形单位的平均大小与反映心肌氧代谢的斑片状NADH荧光单位的平均大小顺序相同。此外，在心肌细胞壁切面上，观察到了外膜肌和内膜肌之间的过渡性NADH活性。NADH荧光出现和消失的时间常数表明，心肌细胞比心肌细胞更容易缺氧。