异氟醚预处理延迟相对兔心肌缺血再灌注损伤的保护作用

Effect of isoflurane delayed preconditioning on myocardial ischemia reperfusion injury in rabbits

目的:探讨异氟醚预处理延迟相对兔心肌缺血再灌注损伤的保护机制。方法:将30只健康新西兰雄性大白兔随机均分成3组:假手术组、缺血再灌注组(I/R组)、2.0%异氟醚预处理组(预处理组)。假手术组吸入100%氧气2h,24h后仅行左冠脉套线而不阻断160min,I/R组吸入100%氧气2h,24h后行左冠状动脉前降支阻断40min,再灌注120min,预处理组吸入2.0%异氟醚+100%氧气2h,24h后处理同I/R组。各组分别于左冠前降支阻断前20min(T1)、左冠前降支阻断20min(T2)、左冠前降支阻断40min(T3)、心肌再灌注1h(T4)心肌再灌注2h(T5)5个时点抽取颈内动脉血测定血浆中TNF-α含量。再灌注结束后观察心肌细胞超微结构的变化,免疫印迹法测心肌p38MAPK活性水平,同时用伊文思蓝和TTC染色法测心肌梗死面积。结果:与I/R组比,预处理组p38MAPK表达降低(P<0.05),心肌梗死面积减少(P<0.05),心肌细胞超微结构损伤减轻,TNF-α含量明显降低(P<0.05)。结论:异氟醚预处理延迟相通过抑制心肌p38MAPK的活性,减少TNF-α生成来减轻心肌缺血再灌注损伤发挥保护作用。

Objective To investigate the protective effect of isoflurane delayed preconditioning on myocardial ischemia reperfusion injury and the potential mechanism in rabbits. Methods Thirty New Zealand male white rabbits were randomly assigned to 3 groups：Control group;I/R group; and 2. 0 % isoflurane group. Isoflurane group was exposed to 2. 0 % isoflurane- 100 % oxygen for 2 hours. Control group and I/R group were exposed to 100% oxygen for 2 hours and served as untreated controls. Twenty-four hours later I/R group coronary occlusion followed by 2 hours of reperfusion. at 20 minutes before the occlusion（ T1 ） , 20 minutes occlusion （ T3 ） , 1 hours after the reperfusion （ T4 ） , and isoflurane group underwent 40 minutes of Blood samples were taken from the arterial line after the occlusion （T2） , 40 minutes after the and 2 hours after the reperfusion （ T5 ） to determine the plasma level of TNF-α. At the end of the reperfusion, infarct size and area at risk were defined by Evans and TI＇C staining. The heart was harvested and levels of the p38MAPK activity were determined by Western blot, and uhrastructures were observed under the electron microscope. Results The p38MAPK activity of isoflurane group was significantly lower than that of I/R group （P 〈 0.05 ）. Isoflurane significantly （ P 〈0.05 ） reduced the infarct size（ 19.7% ± 2.8% in isoflurane group） of the left ventricular area at risk as compared with the controls （37.8% ±1.7% in I/R group）. The injury of I/R group was worse than that of isoflurane group under the light microscope. Isoflurane group had a lower level of TNF-α than I/R group. Conclusion Isoflurane can inhibit p38MAPK activity during myocardial ischemia reperfusion and modulate the cytokine expression, which may be one of the molecular mechanisms of isoflurane delayed preconditioning on cardioprotection.