乳化异氟醚后处理对大鼠肺缺血再灌注时线粒体功能的影响：离体实验

Effect of emulsified isoflurane post-conditioning on mitochondrial function during lung ischemiareperfusion in rats： an in vitro experiment

目的评价乳化异氟醚后处理对大鼠离体肺缺血再灌注时线粒体功能的影响。方法SPF级健康雄性SD大鼠24只，体重250～320 g。取肺后连接到灌流系统上，采用随机数字表法分为4组（n＝6）：对照组（C组）、肺缺血再灌注组（I/R组）、乳化异氟醚后处理组（EI组）和脂肪乳后处理组（IL组）。先平衡20 min，状态稳定后，C组持续灌注105 min，其余3组通过停灌45 min，再灌注60 min的方法制备离体肺缺血再灌注损伤模型；再灌注阶段I/R组使用普通灌流液，EI组用含1.68 mmol/L乳化异氟醚的灌流液再灌注，IL组用等体积含30%脂肪乳的灌流液再灌注。于平衡末（T0）、再灌注即刻（T1）、再灌注30 min（T2）和再灌注60 min（T3）时记录PaO2、气道阻力、肺顺应性和VT，T3时取右上叶肺组织测定肺湿重/干重比值（W/D比值），取右中叶肺组织，光镜下观察肺组织病理学结果；采用化学荧光法检测肺组织活性氧（ROS）含量，采用分光光度法检测肺组织NAD＋含量和ATP含量。结果与C组比较，I/R组、EI组和IL组T1～3时PaO2、肺顺应性和VT降低，气道阻力升高，T3时W/D比值和肺组织ROS含量增加，NAD＋和ATP含量减少（P〈0.05）；与I/R组和IL组比较，EI组T2，3时PaO2、肺顺应性和VT升高，气道阻力降低，T3时W/D比值和ROS含量减少，NAD＋与ATP含量增加（P〈0.05）。EI组肺组织病理学损伤较I/R组减轻。结论乳化异氟醚后处理减轻离体大鼠肺缺血再灌注损伤的机制与其降低线粒体功能障碍有关。

Objective To evaluate the effect of emulsified isoflurane post-conditioning on the mitochondrial function during lung ischemia-reperfusion （I/R） in rats in an in vitro experiment. Methods Twenty-four SPF healthy male Sprague-Dawley rats, weighing 250-300 g, were used in the study. After the animals were anesthetized, the lungs were removed, connected to the perfusion system and then divided into 4 groups （n= 6 each） using a random number table： control group （group C） , group I/R, emulsified isoflurane post-conditioning group （group EI） and intralipid post-conditioning group （group IL）. After 20 min of equilibration, the lungs were continuously perfused for 105 min in group C, and the lungs were subjected to 45 min ischemia followed by 60 min reperfusion to establish the model of lung I/R injury in the other three groups. During the reperfusion period, the common perfusate was used in group I/R, the perfusate containing 1.68 mmol/L emulsified isoflurane was used in group El, and the equal volume of perfusate containing 30% intralipid was used in group IL. At the end of the equilibration （To ） , immediately after beginning of reperfusion （ T1 ） and at 30 and 60 min of reperfusion （T2,3 ）, the arterial oxygen partial pressure （ PaO2 ） , airway resistance, pulmonary compliance and tidal volume （ VT ） were recorded. The right upper lobe of the lung was removed at T3 for determination of wet to dry weight ratio （W/D ratio）. The right middle lobe of the lung was removed at T3 for pathologic examination with light microscope. The contents of reactive oxygen species （ROS） , NAD＋ and ATP in lung tissues were detected. Results Compared with group C, the PaO2, pulmonary compliance and Vr were significantly decreased, and the airway resistance was increased at T1-3, and the W/D ratio and ROS content were increased, and NAD＋ and ATP contents were decreased at T3 in I/R, El and IL groups （P〈0.05）. Compared with I/R and IL groups, the PaO2, pulmonary compliance and VT were significantly increased, and the airway resistance was decreased at T2,3 , and the W/D ratio and ROS content were decreased, and NAD＋ and ATP contents were increased at T3 in group EI （P〈0.05）. The pathologic changes of lungs were significantly attenuated in group EI as compared with group I/R. Conclusion The mechanism by which emulsified isoflurane post-conditioning attenuates lung I/R injury is related to decrease in mitochondrial dysfunction in rats in an in vitro experiment.