七氟烷预处理对糖尿病大鼠离体心肌缺血-再灌注损伤的影响

Impact of sevoflurane preconditioning on myocardial ischemia-reperfusion injury in isolated rats with diabetes mellitus

目的观察七氟烷预处理对糖尿病(DM)模型大鼠离体心肌缺血-再灌注(I-R)损伤的影响。方法雄性SD大鼠64只,随机均分为四组:N组,非DM,I-R;NS组,非DM,I-R前七氟烷预处理;D组,DM,I-R;DS组,DM,I-R前七氟烷预处理。采用大鼠离体心脏Langendorff灌注模型,行全心缺血30min,再灌注60min。NS组和DS组于缺血前用2.4%七氟烷预充饱和的K-H液灌注10min,洗脱5min。记录各组平衡末及再灌注15、60min的心功能指标,TUNEL法检测再灌注15min心肌细胞凋亡,Western blot法半定量检测磷酸化和总丝氨酸/苏氨酸激酶(Akt),再灌注末采用氯化三苯基四氮唑染色分析心肌梗死面积百分比。结果与N组相比,NS组再灌注15min心肌细胞凋亡减少,伴随磷酸化Akt表达增强(P<0.05),再灌注末心功能指标改善(P<0.05),心肌梗死面积减小(P<0.05)。D组与DS组间上述指标未见统计学差异(P>0.05)。与N组比较,D组基础心功能指标降低(P<0.05),而再灌注15min心肌细胞凋亡减少伴随磷酸化Akt表达增强,再灌注末心功能恢复增强(P<0.05),心肌梗死面积下降(P<0.05)。结论七氟烷预处理可以减轻非DM大鼠心肌I-R损伤;其在DM大鼠没有显示心肌保护作用,心肌Akt活化水平不能有效提高可能是其机制之一。

Objective To investigate the effect of sevoflurane preconditioning on myocardial ischemia-reperfusion（LR） injury in isolated rats with diabetes mellitus （DM）. Methods Sixty-four male SD rats were randomly divided into four groups of D（DM rats with I-R injury） ,DS（DM rats with sevoflurane preconditioning and I-R injury）, N（nonDM rats with I-R injury） and NS（nonDM rats with preconditioning and I-R injury）. The hearts isolated from all rats were experienced ischemia for 30 minutes and followed by reperfusion. The hearts in groups of NS and DS were perfused with K-H solution saturated with 2.4% sevoflurane for 10 minutes before ischemia, which was followed by 5 minutes washout. The cardiac function variables were measured at 20 minutes of equilibrium,15,60 minutes of reperfusion. Cardiocyte apoptotic index（CAD and expressions of phosphorylated Akt（p-Akt） and total Akt were measured with TUNEL staining and Western blot analysis at 15 minutes of reperfusion. The infarcted size of the myocardium（ISM） was measured with TTC staining at the end of reperfusion. Results Compared with group N, group NS showed significant decreases in CAI and ISM companied by an increase of expression of p-Akt at 15 minutes of reperfusion and an improved hemodynamic function（P〈0. 05）. There were no significant differences in the parameters mentioned above between groups of D and DS（P〉0. 05）. Compared with group N, group D showed significant decreases in CAI and ISM companied by increased expression of p-Akt at 15 minutes of reperfusion and improved hemodynamic function（P〉0. 05）. Conclusion Sevoflurane preconditioning can effectively protect the hearts from I-R injury in isolated hearts from normal rats. Sevoflurane preconditioning can not protect the hearts of DM rats, for which lossing increase of Akt activation may be one of the mechanisms.