乳化异氟醚预处理对兔心肌缺血再灌注损伤的影响

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

目的探讨乳化异氟醚预处理对兔心肌缺血再灌注损伤的影响。方法健康雄性新西兰大白兔32只，体重2．0～2．5kg，阻断冠状动脉1h，再灌注3h建立心肌缺血再灌注损伤模型，随机分为4组（n=8），缺血再灌注组（1R组），异氟醚组（1组）吸入异氟醚，维持呼气末浓度0．5MAC30min，洗脱15min后缺血1h再灌注3h；乳化异氟醚组（EI组）静脉注射（1ml／s）8％乳化异氟醚4—6ml至呼气末浓度0．5MAC，以4～6ml·kg^-1·h^-1静脉输注乳化异氟醚维持呼气末浓度0．5MAC30min，洗脱15min后缺血1h再灌注3h；脂肪乳组（L组）静脉输注（5ml·k^-1·h^-1）与乳化异氟醚等量的30％脂肪乳注射液30min，停止静脉输注脂肪乳15min后缺血1h再灌注3h。再灌注3h后测定血清磷酸肌酸激酶（CK）、乳酸脱氢酶（LDH）活性和一氧化氮（NO）浓度，并计算梗死区心肌与左心室干重比值、梗死区心肌与缺血区心肌干重比值。结果与IR组比较，Ⅰ组和EI组梗死区心肌与左心室干重比值、梗死区心肌与缺血区心肌干重比值均明显降低，血清CK和LDH活性降低，NO浓度增加（P〈0．05），L组上述指标差异无统计学意义（P〉0．05）；Ⅰ组和EI组各指标差异无统计学意义（P〉0．05）。结论8％乳化异氟醚预处理可减轻兔心肌缺血再灌注损伤，其机制可能与NO生成量增加有关。

Objective To investigate the effects of emulsified isoflurane preconditioning on myocardial ischemia-reperfusion （I/R） injury in rabbits. Methods Thirty-two male adult New Zealand white rabbits weighing 2.0-2.5 kg were randomly divided into 4 groups （ n = 8 each） ： group Ⅰ I/R; group Ⅱ isoflurane; group Ⅲ emulsified isoflurane and group Ⅳ intralipid. The animals were anesthetized with intramuscular ketamine 7 mg/kg, intubated and mechanically ventilated with 100% O2. Anesthesia was maintained with intravenous infusion of midazolam, ketamine and vecuronium. I/R was produced by 1 h occlusion of anterior descending branch of left coronary artery （LAD） followed by 3 h reperfusion. Group Ⅱ received 1.1% isoflurane inhalation for 30 min followed by 15 min wash-out before I/R; group Ⅲ received a bolus of 8% emulsified isoflurane 4-6 ml injected iv over 4-6 seconds followed by 30 min infusion at 4-6 ml· kg^-1 · h^-1 and 15 min wash-out before I/R; group Ⅳ received 30% intralipid infusion at 5 ml· kg^- 1· h^-1 for 30 min followed by 15 min wash-out before I/R. At the end of 3 h reperfusion blood samples were taken for determination of plasma lactate dehydrogenase （LDH） and ereatine kinase （CK） activities and NO concentration and myocardial infarct size was determined. Results The myocardial infarct size was smaller, and plasma LDH and CK activities were significantly decreased while plasma NO concentration was increased in isoflurane inhalation （ Ⅱ ） and emulsified isoflurane （Ⅲ ） group as compared with I/ R group （ Ⅰ ） . Conclusion 8% emulsified isoflurane preconditioning can protect myoeardium against I/R injury through NO release.