解偶联蛋白2在七氟醚后处理心肌保护作用中的机制研究

Mechanism of UCP2 in myocardial protection of sevoflurane postconditioning

目的 探讨解偶联蛋白2(UCP2)在雄性小鼠七氟醚后处理(SPostC)心肌保护作用中的机制。方法 选取健康雄性小鼠45只,按照随机数字表法分为假手术组即sham组,在体建立缺血再灌注组即I/R组,在I/R组的基础上给予1MAC七氟醚的I/R+SPostC组,每组15只。测定3组小鼠主动脉内径和左室射血分数;采用TTC+Evans Blue染色法测定心肌梗死面积;HE染色法观察心肌组织结构;透射电镜下观察线粒体结构;活性氧试剂盒测定心肌细胞能量代谢。蛋白质印迹法检测3组UCP2蛋白表达水平。结果(1)I/R+SPostC组的主动脉内径和左室射血分数变化率低于I/R组(P<0.05)。I/R+SPostC组小鼠的心肌梗死面积小于I/R组(P<0.05)。(2)与sham组相比,I/R组小鼠心肌组织排列较紊乱,部分心肌纤维断裂,心肌细胞肿胀,空泡变性。与I/R组相比,I/R+SPostC组小鼠心肌组织排列紊乱、心肌细胞肿胀、心肌纤维断裂及炎细胞浸润程度减轻。(3)电镜下线粒体结构:I/R组肌丝溶解、断裂,线粒体肿胀;I/R+SPostC组线粒体结构优于I/R组,线粒体形态基本完整,轻度肿胀,肌丝少量溶解。(4)与I/R组相比,I/R+SPostC组ROS生成减少(P<0.05)。(5)与sham组相比,I/R组UCP2蛋白表达增高,I/R+SPostC组UCP2表达水平进一步增高(P<0.05)。结论UCP2蛋白的表达上调可能与SPostC减轻心肌缺血再灌注损伤的保护作用有关。

Objective To explore the mechanism of uncoupling protein 2(UCP2) in myocardial protection of sevoflurane postconditioning(SPostC) in male mice.Methods A total of 45 healthy male mice were randomly divided into the three groups(n=15).Sham group was sham-operated group.Ischemia-reperfusion group was established in vivo,and sevoflurane post-treatment group(SPostC) was given 1MAC sevoflurane on the basis of I/R.The diameter of aorta and ejection fraction were recorded by echocardiography,and the infarct size was measured by TTC+Evans blue staining.Myocardial tissue structurewas recorded by HE staining method.Mitochondrial structure was observed under transmission electron microscope.Energy metabolism of cardiomyocytes was determinated by ROS kits,and the expression of UCP2 protein in the three groups were detected by Western blot method.Results(1)The change rate of aortic diameter and ejection fraction in I/R+SPostC group was smaller than that in I/R group(P<0.05).The myocardial infarct size was decreased in I/R+SPostC group(P<0.05).(2)Myocardialmicro-structure:compared with sham group,the arrangement of myocardialtissue was more disordered,and the myocardial fibers were broken,and cardiomyocytes were swollen and vacuolated.Compared with I/R group,the degree of myocardial disorder,cardiomyocyte swelling,myocardialfiber rupture and inflammatory cell infiltration in I/R+SPostC group were alleviated.(3)Mitochondrial structure under electron microscope:the structure of mitochondria in I/R+SPostC group was better than that in I/R group.The morphology of mitochondria was basically intact with slight swelling,and a small amount of myofilament was dissolved.(4)Compared with I/R group,ROS production in I/R+SPostC group was decreased(P<0.05).(5)Compared with sham group,the expression of UCP2 protein in I/R+SPostC group was higher than that in I/R group,and the expression level of UCP2 in I/R+SPostC group was further up-regulated(P<0.05).Conclusion The up-regulation of UCP2 protein expression may be related to protective effect of SPostC on myocardial ischemia-reperfusion injury.