七氟醚后处理对大鼠心肌缺血-再灌注时 AKT/GSK3β/mTOR 表达的影响

摘要

Objective To investigate the role of AKT/GSK3β/mTOR signaling molecule in myocardial protection of sevoflurane postconditioning.Methods Thirty-nine male Sprague-Dawley rats,weighing 200-250 g,installed in vivo myocardial ischemia-reperfusion model by left anterior de-scending coronary occlusion for 30 min.Rat hearts were randomly divided into 3 groups (n = 13 ):sham control group (group Sham),purely ischemia-reperfusion group (group IR),sevoflurane post-conditioning group (group SPC).With the exception of group Sham,each group was subjected to oc-clusion for 30 min followed by 2 h reperfusion.Group SPC was subjected to sevoflurane postcondi-tioning:2.4% sevoflurane was inhaled for 1 5 min starting from the end of ischemia until 1 5 min after beginning of reperfusion,while 33% oxygen was inhaled in the other groups.At the end of 2 h reper-fusion,cardiac function was evaluated by two-dimensional echocardiography,myocardial infarction size was measured by using 1% 2,3,5-triphenyltetrazolium chloride triazole (TTC),myocardial ultra-structural alterations was detected by transmission electron microscopy (TEM),cardiomyocytes ap-optosis was examined by terminal deoxynucleotidyl nickend labeling (TUNEL),the expressions of p-AKT/t-AKT, p-GSK3β/t-GSK3β, p-mTOR/t-mTOR,Bcl-2 and Bax proteins was measured by Western blot.Results Compared with group Sham,cardiac function was deteriorated,myocardial in-farct size was increased,cardiomyocyte mitochondrial damage was increased,positive apoptotic car-diomyocyte was increased,the expression of Bcl-2 was down-regluated,and the expressions of p-AKT/t-AKT,p-GSK3β/t-GSK3β,p-mTOR/t-mTOR and Bax were up-regluated in group IR (P <0.05).Compared with group IR,cardiac function was improved,myocardial infarct size was de-creased,cardiomyocyte mitochondrial damage was decreased,positive apoptotic cardiomyocyte was decreased,the expression of Bax was down-regluated,and the expressions of p-AKT/t-AKT,p-GSK3β/t-GSK3β,p-mTOR/t-mTOR and Bcl-2 were up-regluated in group SPC (P < 0.05 ). Conclusion Sevoflurane postconditioning can mitigate ischemia-reperfusion injury to in vivo rat hearts,decreased cardiomyocyte mitochondrial damage,inhibited cardiomyocyte apoptosis,and its mechanism was related to the activation of AKT/GSK3β/mTOR signaling molecule.%目的：观察七氟醚后处理对大鼠心肌缺血-再灌注时蛋白激酶 B/糖原合成酶激酶-3β/哺乳动物雷帕霉素靶蛋白(AKT/GSK3β/mTOR)表达的影响。方法雄性 SD 大鼠39只,体重200~250 g,在体结扎左冠状动脉前降支30 min 建立心肌缺血-再灌注损伤模型。采用随机数字表法分为三组(n=13)：假手术组(Sham 组)、单纯缺血-再灌注组(IR 组)、七氟醚后处理组(SPC 组)。除Sham 组,其余组均缺血30 min 后再灌注2 h。SPC 组进行七氟醚后处理：于缺血末至再灌注开始后15 min 持续吸入2.4%七氟醚,而其它二组吸入氧浓度33%的空气。再灌注2 h 时,二维心脏超声评估各组心功能,1%2,3,5氯化三苯基四氮唑测定心肌梗死范围,透射电镜观察心肌细胞超微结构,原位末端转移酶标记法测定心肌细胞凋亡,Western blot 法测定蛋白表达,包括磷酸化 AKT(p-AKT)/总 AKT (t-AKT),磷酸化 GSK3β(p-GSK3β)/总 GSK3β(t-GSK3β),磷酸化 mTOR (p-mTOR)/总 mTOR(t-mTOR),B 淋巴细胞瘤-2基因(Bcl-2)和 Bcl-2相关 X 蛋白(Bax)。结果与Sham 组比较,再灌注未 IR 组心功能恶化,心肌梗死范围增加,心肌线粒体损伤加重,凋亡阳性细胞增多,Bcl-2表达明显下调,p-AKT/t-AKT、p-GSK3β/t-GSK3β、p-mTOR/t-mTOR 和 Bax 表达明显上调(P <0.05)。与 IR 组比较,再灌注未 SPC 组心功能明显改善,心肌梗死范围减少,心肌线粒体损伤减弱,凋亡阳性细胞减少,Bax 表达明显下调,p-AKT/t-AKT、p-GSK3β/t-GSK3β、p-mTOR/t-mTOR 和 Bcl-2表达明显上调(P <0.05)。结论七氟醚后处理对在体大鼠心肌缺血-再灌注损伤具有明显的保护作用,能够减少心肌细胞线粒体损伤,抑制心肌细胞凋亡,且其机制可能与其激活AKT/GSK3β/mTOR 信号分子有关。