异氟醚预处理延迟相对兔缺血再灌注心肌TNF-α水平及Caspase-3蛋白表达的影响

Effects of Isoflurane Delayed Preconditioning on Caspase-3 Protein Expression and TNF-α Level in Ischemia-reperfusion Myocardium of Rabbit

目的探讨异氟醚预处理延迟相对缺血再灌注心肌的保护作用及其机制。方法30只健康新西兰雄性大白兔随机分成3组:假手术组(C组)、缺血再灌注组(I/R组)、2.0%异氟醚预处理组(S组),每组10只。C组仅开胸160min,I/R组行左冠脉阻断40min,再灌注120min,S组吸入2.0%异氟醚2h,24h后处理同I/R组。各组分别于左冠脉阻断前20min(T1)、左冠脉阻断20min(T2)、左冠脉阻断40min(T3)、再灌注1h(T4)、再灌注2h(T5)五个时点抽取血测血清TNF-α水平。再灌注结束后免疫印记法测心肌Caspase-3蛋白表达水平,用伊文思蓝和TTC染色测心肌梗死面积。结果与I/R组比,S组TNF-α水平降低(P<0.05),Caspase-3表达降低(P<0.05),心肌梗死面积减少(P<0.05)。结论异氟醚预处理延迟相通过下调心肌Caspase-3表达和TNF-α生成来减轻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 mechanisms in rabbit. Methods Thirty males New Zealand white rabbits were randomly assigned to 3 groups. Control group; I/R group;2.0% Isoflurane group. Group 3 was exposed to 2.0% isoflurane-100% oxygen for 2 h.Group 1 and group 2 were exposed to 100% oxygen for 2 h and served as untreated controls. Twenty-four hours later group 2 and group 3 underwent coronary occlusion for 40 min followed by reperfusion for 2 h. Blood samples were taken from arterial line at 20min before occlusion （T1）,20 min after occlusion（T2）,40 min after occlusion（T3）,1 h after reperfusion（T4）and 2 h after reperfusion（T5）for determination of the plasma levels of TNF-α. At the end of the reperfusion,infarct size（IS）and area at risk（AAR）were defined by Evans and TTC staining. The hearts was harvested and levels of the Caspase-3 expression were determined by Western Blot analysis. Results The Bcl-2 level of group 3 was significantly lower than that of group 2 （P〈0.05）.Isoflurane significantly（P〈0. 05）reduced infarct size（19.7%±2.8% in group 3）of the left ventricutar area at risk as compared with control（37.8%±1.7% in group 2）. Group 3 had a lower levels of TNF-α than that of Group 2. Conclusion Isoflurane could inhibit Caspase-3 expression and modulate the procytokine level during ischemia reperfusion, which may be one of molecular mechanisms of Isoflurane delayed preconditioning on cardioprotection.