Effect of emulsified isoflurane preconditioning on myocardial ischemia-reperfusion injury in rabbits

Objective To evaluate the effect of emulsified isoflurane preconditioning on myocardial iachemia-reperfusion (I/R) injury in rabbits.Methods Thixty-two male New Zealand white rabbits weighing 2.5-3.0 kg were randomly divided into 4 groups(n=8 each):group Ⅰ I/R;group Ⅱ isoflurane preconditioning (group Ⅰ);group Ⅲ emulsified isoflurane preconditioning (group EI) and group Ⅳ intralipid (group INT).Myocardial I/R was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 180 min of reperfusion.After 30 min of post-preparation equilibration.the animal inhaled 3%isoflurane for 30 min followed by 15 min washout in group Ⅰ(group Ⅱ);8% emulsified isoflurane 8-10 ml was injected iv at 1 ml/s followed by continuous infusion at 6-8 ml·kg-1·h-1,maintaining end-tidal isoflurane concentration at 1.28% for 30 min in group EI (groupⅢ);30% intralipid 9 ml was injected iv at 1 ml/s fullowed by continuous infusion at 7 ml·kg-1·h-1 for 30 min in group INT (group IV).HR and BP were monitored and recorded at 30 min of post-preparatory equilibration(T0),before ischemia(T1),at the beginning of ischemia(T2),at 30 min ofischemia(T3),60,120 and 180 min of reperfnsion(T4,5,6).HR-SP product (RPP) was calculated.Infarct size (IS) was determined by TIC staining.Blood samples were taken from carotid artery at T6 for determination of serum CK and LDH activities and IL-6 and IL-10 concentrations.Results HR,MAP and RPP were decreasing during T2-6, but there was no significant difference in HR, MAP and RPP among the 4 groups.The infarct size was signigicantly smaller, serum CK and LDH activities and IL-6 concentration were significantly lower while serum IL-10 concentration was significantly higher in group I and EI than in group I/R and INT.Conclusion Emulsified isoflurane preconditioning can attenuate myocardial I/R injury by inhibiting inflammatory response. Key words: Isoflurane; Fat emulsions, intravenous; Ischemic preconditioning; Myocardial reperfusion injury