Three-dimensional microstructural abnormality of the coronary capillary network after myocardial reperfusion- A Three-Dimensional Confocal Laser Microscopic Study -

背景。以往的实验和临床研究报道，尼可地尔是一种对三磷酸腺苷（ATP）敏感的K^+通道开放剂，对心肌缺血后微血管功能和临床结局有有益的影响。我们评估了尼可地尔静脉给药对早期心肌再灌注后毛细血管三维结构特征和毛细血管体积的影响。方法与结果。采用开胸麻醉大鼠心脏，阻断左前降支7 min后再灌注。封堵和再灌注时静脉滴注尼可地尔或生理盐水。心脏停搏后，整个冠状动脉微血管充满造影剂。利用激光共聚焦扫描显微镜对所有样品的毛细血管进行三维、对照区和再灌注区观察。根据三维图像计算毛细管体积分数。尼可地尔组和生理盐水组再灌注区毛细血管均出现特征性的结构改变。尼可地尔组大鼠再灌注区毛细血管体积分数较尼可地尔组明显降低[12.7±7.2%比18.1±5.3% (p<0.01)]。静脉注射尼可地尔有利于减轻毛细血管损伤。

Background. Previous experimental and clinical studies have reported that Nicorandil, an adenosine triphosphate (ATP)-sensitive K^+ channel opener, exerts beneficial effect on microvascular function and clinical outcome after myocardial ischemia. We assessed whether intravenous administration of Nicorandil affect capillary three-dimensional (3-D) architectural characteristics and capillary volume, after early myocardial reperfusion.Methods and Results. Using opened-chest anesthetized rats' hearts, the left anterior descending artery was occluded for 7 min followed by reperfusion. Nicorandil or saline was infused intravenously during occlusion and reperfusion. Entire coronary microvasculature was filled with contrast medium, after the hearts were arrested. Capillaries were observed 3-dimensionally, in control area and reperfused area in all samples utilizing confocal laser scanning microscopy. Capillary volume fraction was computed from 3-D images. Reperfused area in both nicorandil and saline groups showed characteristic architectural changes in capillaries. In nicorandil group, capillary volume fraction in the reperfused area was significantly reduced in saline group, compared with nicorandil group [12.7±7.2% versus 18.1±5.3% (p<0.01)].Conclusions. Intravenous nicorandil administration beneficially affects capillary damages.