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

背景尼可地尔是一种三磷酸腺苷（ATP）敏感性钾通道开放剂，既往的实验和临床研究已报道尼可地尔对心肌缺血后的微血管功能和临床结局具有有益作用。我们评估了静脉注射尼可地尔是否影响早期心肌再灌注后毛细血管三维（3-D）结构特征和毛细血管体积。使用开胸麻醉的大鼠心脏，阻断左前降支动脉7 min，然后再灌注。在闭塞和再灌注期间静脉输注尼可地尔或生理盐水。心脏停搏后，用造影剂填充整个冠状动脉微血管。利用共聚焦激光扫描显微镜对所有样本的对照区和再灌注区进行三维观察。毛细血管体积分数从3-D图像计算。尼可地尔和生理盐水组的再灌注区均显示毛细血管的特征性结构变化。尼可地尔组再灌注区毛细血管体积分数显著低于生理盐水组[12.7±7.2% vs 18.1±5.3%（p<0.01）]。尼可地尔静脉给药有益于影响毛细血管损伤。

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.