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目的:探讨电磁脉冲(EMP)对SD大鼠心肌闰盘及主要连接蛋白Cx43的影响。方法:将雄性SD大鼠35只,随机分为对照组和EMP辐照组,EMP辐照组又分为照后即刻、1h、3h、6h、12h、24h组,每组5只大鼠。应用EMP模拟发生器对EMP辐照组大鼠进行辐照,场强为200 kV/m、前沿15 ns、脉宽7-8 ns、脉冲次数200次,脉冲间隔为7 s,麻醉后取大鼠左心室,采用硝酸镧示踪法和透射电子显微镜观察大鼠心肌闰盘(ID)结构的变化,用Real-Time PCR方法和Western blot方法检测EMP辐照后,大鼠连接蛋白Cx43在转录水平和蛋白水平表达量的变化情况。结果:电镜下正常对照组大鼠心肌ID处未见硝酸镧颗粒沉积;EMP组大鼠ID处可见硝酸镧颗粒,且随时间的延长,硝酸镧颗粒沉积量逐渐增多,以照后6h组硝酸镧颗粒沉积量达最大,然后硝酸镧颗粒沉积量随时间延长逐渐减少,24h组恢复正常。心肌细胞Cx43的mRNA表达水平在EMP照后1h和6h明显增高,分别是对照组的1.95、3.10倍(P<0.05);照后即刻、3h、12h、24h表达水平与对照组相比差异无统计学意义(P>0.05)。Western blot结果为照后即刻、1h、3h和6h组大鼠心肌细胞Cx43蛋白表达量与对照组比较显著增加,12h、24h与对照组相比差异无统计学意义(P>0.05)。结论:EMP可使心肌闰盘结构发生改变,上调Cx43蛋白的mRNA水平和蛋白表达量。
Objective: To investigate the effect of electromagnetic pulse (EMP) on the myocardial intercalated disc and the major connexin Cx43 in SD rats. Methods: Thirty-five male Sprague-Dawley rats were randomly divided into control group and EMP irradiation group. EMP irradiation group was divided into 5 groups of rats: immediately, 1h, 3h, 6h, 12h and 24h. EMP simulator was used to irradiate rats in EMP irradiation group with a field strength of 200 kV / m, a leading edge of 15 ns, pulse width of 7-8 ns, pulse number of 200 and pulse interval of 7 s. Rat left ventricle. The structure of intercalary disc (ID) was observed by Lanthanum nitrate tracer and transmission electron microscopy. Real-time PCR and Western blot were used to detect the expression of Cx43 Level and level of protein expression changes. Results: There was no lanthanum nitrate deposition in the myocardial ID of rats in the normal control group under electron microscope. Lanthanum nitrate particles could be observed in the ID of rats in EMP group. With the prolongation of time, lanthanum nitrate deposition gradually increased. Lanthanum particles deposited the largest amount, and then deposition of lanthanum nitrate particles gradually decreased over time, 24h returned to normal. The mRNA expression of Cx43 in cardiomyocytes increased significantly at 1h and 6h after EMP irradiation, which were 1.95 and 3.10 times higher than those in control group (P <0.05). The expression levels of Cx43 mRNA at 3h, 12h and 24h after irradiation were significantly lower than those in control group Statistical significance (P> 0.05). Western blot results showed that the expression of Cx43 protein in myocardial cells of rats in 1h, 3h and 6h groups increased significantly compared with that of control group, but there was no significant difference between 12h and 24h groups (P> 0.05). Conclusion: EMP can change the myocardial intercalated disc structure and up-regulate the mRNA and protein expression of Cx43 protein.