Objective :To observe the tolerance of the isolated hearts of pregnant mice on ischemia indoctrination injury and the protective effects of different concentrtion remifentanil pretreatment against pregnant rats myocardial ischemia reperfusion injury. Methods : 40 male SD rats were randomly divided into 4 groups, 10 non-pregnant mice were selected as cantrol group. 20 days after the pregnancy, 30 pregnant rats were randomly divided into 3 groups: no remifentanil preconditioning group (RF0 group); low concentration remifentanil group (RF, group) and high concentration remifentanil group (RF2 group). After anesthesia,the hearts were immediately removed out to establish the Langendorff isolated heart perfusion model.After 20 min of perfusion for stabilization in each group,the hearts of the contronl group and the no remifentanil preconditioning group were consistently perfused with K-H solution saturated with 95 ％O2 and 5 ％CO2 at 37℃ .After being stabilization perfused for 20 min the hearts were subjected to 30 min global ischemia by suspension of perfusion followed by 45 min reperfusion. In the fentanyl pretreatment groups (FPC1, FPC2group) and remifentanil pretreatment group(RPC1,RPC2 group),the hearts were perfused with 20 or 40μg/L fentanyl or remifentanil solution before ischemia-reperfusion respectively. The left ventricular systolic pressure (LVSP) ,left ventricular and diastolic pressure (LVEDP) and coronary flow (CF) were monitored continuously. Coronary effluent was collected from 15 min of stabilization to 15 min of reperfusion for determination LDH activity. At the end of 45 min reperfusion.their hearts were removied for determination for myocardial MDA content and harvested for determination of myocardial infarct size. At the same time, the heart sections were observed to examine ultrastructure using electron microscopy. Results: At the end of 20min stabilization, activity of LVEDP , LVSP and LDH were not significantly changed in than those each group (P＞0.05). After reperfusion ,LVEDP, LVSP recovered significantly better in the fentanyl pretreatment groups (FPC1, FPC2 group) or remifentanil pretreatment group (RPC1 , RPC2 group) than control group (C group) (P＜ 0. 05). The myocardial MDA content ,LDH release were significantly lower than those in the fentanyl pretreatment groups (FPC1 , FPC2 group ) or remifentanil pretreatment group (RPC1 , RPC2 group) (P＜0. 05). Compared with the control group (C group), the infarct area was significantly smaller, the myocardial ultrastructure was well-preserved in the fentanyl pretreatment groups (FPC1, FPC2 group) or remifentanil pretreatment group (RPC1 , RPC2 group) (P＜0. 05). The higher concentration fentanyl or remjfentanil solution had better cardioprotective effects than lower concentration solution. Compare with fentanyl, remifentanil had beter cardioprotective effects (P ＜ 0. 05).Conclusion: The tolerance of pregnant rat isolated heart against ischemic injury indoctrination are decreased and remifentanil have dose-depended protective effects on myocardial ischemia reperfusion of isolated myocardial of pregnant rats.%目的:探讨孕鼠离体心脏对缺血再灌输损伤的耐受及不同浓度瑞芬太尼预处理对孕鼠离体心功能及心肌缺血再灌注损伤的保护作用.方法:将雌性SD大鼠40只中非孕鼠10只做为空白对照组,其余孕鼠30只,于孕后第20天随机分为3组:无瑞芬太尼预处理组(RF0组)、低浓度瑞芬太尼组(RF1组)和高浓度瑞芬太尼组(RF2组),每组10只.麻醉后开胸取心脏,建立Langendorff孕鼠离体心脏灌注模型.每组均灌注平衡20min,对照组(Con组)与无瑞芬太尼预处理组(RF0组)用95%O2和5%CO2饱和的K-H液持续灌注20min,停灌30min再灌注45min;浓度瑞芬太尼组(RF1组)、高浓度瑞芬太尼组(RF2组)缺血前分别用含瑞芬太尼20μg/L或40μg/L的95%O2和5%CO2饱和K-H液灌注20min,全心缺血30min,复灌45min;记录各组左室舒张末压(LVEDP),左室收缩压(LVSP)及冠脉流量(CF)变化,测定平衡15min后到再灌注后15min内冠脉流出液乳酸脱氢酶(LDH)活性,测定再灌注后45min时的心肌丙二醛(MDA)含量,同时取每组孕鼠心肌做切片,在电镜下观察心肌细胞的超微结构.结果:在平衡20min末,与对照组比较,各组LVEDP、LVSP和LDH的活性均无显著变化(P>0.05);与对照组比较,各组在灌注后各时间点LVEDP升高(P<0.05),LVSP和CF降低(P<0.05),灌注后15min冠脉流出液LDH活性增高(P<0.05),再灌注后45min后心肌MDA含量增高(P<0.05),梗死面积增大(P<0.05),电镜下心肌结构破坏明显;与无瑞芬太尼预处理组比较,两瑞芬太尼预处理组在灌注后各时间点LVEDP降低(P<0.05),LVSP以及CF升高(P<0.05),灌注后15min冠脉流出液LDH活性降低(P<0.05),再灌注后45min后心肌MDA含量降低(P<0.05),梗死面积较小(P<0.05),电镜下心肌结构破坏不明显;与RF1组比较,RF2组保护作用明显(P<0.05);结论:孕鼠离体心脏对缺血再灌输损伤的耐受下降,瑞芬太尼浓度依耐性地保护离体孕鼠全心缺血再灌注损伤.
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