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

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(P0.05).Isoflurane significantly(P0.05)reduced infarct size(19.7%±2.8% in group 3)of the left ventricular area at risk as compared with control(37.8%±1.7% in group 2).Group 3 had a lower levels of TNF-αthan 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.