CGRP改善体外循环中心脏缺血再灌注时的心肌微循环

Changes of Myocardial Microcirculation During Ischemia-reperfusion Associated with Cardiopulmonary Bypass by Using Calcitonin Gene-related Peptide

目的研究体外循环中全心缺血再灌注损伤时心肌微循环的动态变化以及降钙素基因相关肽（ＣＧＲＰ）的心肌保护作用。方法建立猪体外循环心肌缺血再灌注模型，应用激光多普勒微循环血流计，分别于体外循环不同时间点，观测右心耳同一部位的心肌微区灌流量，并同时记录心率和血压；以ＣＧＲＰ作为心肌麻痹液的组成部分，观察其对心肌微区灌流量变化的影响。结果心肌微区灌流量在体外循环开始后与体外循环前相比无统计学差别。再灌注后，心肌微区灌流量显著降低，随再灌注时间的延长逐渐上升至缺血前水平。应用ＣＧＲＰ组在再灌注各时间点的心肌微区灌流量均较对照组明显增高，其变化早于血压的升高，并与心率的变化无关。结论体外循环心脏再灌注后存在心肌微循环障碍，ＣＧＲＰ作为心肌麻痹液的组成部分可改善体外循环心肌再灌注后心脏的微循环功能，从而起到心肌保护作用。

Objective To observe the changes of myocardial microcirculation during ischemiareperfusion associated with cardiopulmonary bypass (CPB) and the effect of calcitonin gene-related peptide (CGRP) on myocardial protection. Methods A pig model of myocardial ischemia-reperfusion injury during CPB was established. Myocardial microvascular perfusion on the right atrium of the pig was detected by a laser doppler flowmeter on six consecutive time during CPB. Heart rate and blood pressure were measured at the same time. CGRP was used as a component of cardioplegia in the study group (CGRP group).Results Myocardial microvascular per fusion was of no statistical difference between after the beginning of CPB and before CPB,while marked decreased when the heart reper fused after 45 minutes' arrest compared with that before myocardial ischemia. It then went up gradually to the level of pre-ischemia 60 minutes after reperfusion. Myocardial microvascular perfusions in the CGRP group on different time during reperfusion period were much higher than those in the control group respectively (P<0.01).The changes of myocardial microvascular perfusion appeared earlier than that of the rising of blood pressure and of no relationship to the heart rate.Conclusion Myocardial microcirculation disorders exist during cardiac ischemia-reperfusion associated with CPB. CGRP as a component of cardioplegia improves myocardial microcirculation during this period and could become a new,potent myocardial protector.