Protective effects of emulsified isoflurane after myocardial ischemia-reperfusion injury and its mechanism in rabbits

Objective:To evaluate the protective effects of 8% emulsified isoflurane after myocardial ischemia-reperfusion injury and its mechanism in rabbits. Methods:Twenty-four male adult New Zealand white rabbits were anesthetized with intravenous injection of 30 mg/kg pentobarbital followed by 5 mg·kg-1·h-1 infusion.All rabbits were subjected to 30 minutes of left anterior descending coronary artery(LAD) occlusion and 3 hours of subsequent reperfusion.Before LAD occlusion,the rabbits were randomly allocated into three groups for preconditioning treatment(eight for each group).The control group (C group) received intravenously 0.9%NaCl for 30 minutes. The emulsified isoflurane group(EI group) received 8% emulsified isoflurane intravenously till 0.64%end-tidal concentration for 30 minutes that was followed by a 15-minute washout period.The Intralipid group(IN group) received 30%Intralipid for 30 minutes.The infarcted area,plasma malondialdehyde(MDA) content,superoxide dismutase activity(SOD) and nitrite concentration after 3-hour myocardial perfusion were recorded simultaneously. Results:For the myocardial ischemia-reperfusion injury animals,the infarcted size in the EI group was significantly reduced(91.9%±8%) as compared with control group (39%±6%,t=5.19,P<0.01).The plasma SOD activity and nitrite concentration in EI group were significantly higher than those in control group(t=2.82,t=8.46,P<0.05),but MDA content was lower in EI group than that in control group (t=2.56,P<0.05). Conclusions:The results indicate that emulsified isoflurane has a cardioprotection effect against ischemiareperfusion injury.This beneficial effect of emulsified isoflurane is probably through NO release and consequently by increase in antioxidation of myocardium.