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目的探讨电磁脉冲(EMP)导致心肌闰盘(ID)改变的规律及机制,为制定EMP的卫生标准以及其医学应用提供实验依据。方法采用EMP模拟发生器,场强为200kv/m、脉冲次数为200次、脉冲间隔2s。雌性SD大鼠54只随机分为7组,其中对照组和照后12h组均为12只,其余组(照后即刻、6、24、36及48h)均为6只。将大鼠于照后即刻、6、12、24、36和48h,采用硝酸镧示踪法和透射电子显微镜观察心肌ID结构的改变。照后12h组,用免疫荧光标记法和激光共聚焦显微镜观察大鼠心肌中Zo-1和Cx40蛋白表达的变化。结果正常对照组大鼠的心肌肌膜完整,肌小节清楚,肌丝排列整齐,细胞连接结构完整,ID连接紧密未见镧颗粒沉积。照后即刻组和6h组的心肌ID间隙增宽不明显,仅见其间隙有少量镧颗粒;照后12h组的心肌ID间隙增宽最明显,ID间隙中充满着大量镧颗粒;照后24h组较照后12h组明显好转,照后48h组已基本恢复正常。照后12h组和对照组的心肌细胞连接处Zo-1、Cx43均有表达,但辐照组两种蛋白的平均荧光强度值均有下降的趋势,且无移位表达。结论EMP辐照可诱导心肌ID间隙时相性增宽及Zo-1和Cx43蛋白的表达下降。
Objective To investigate the regularity and mechanism of cardiac muscle intercalated disc (ID) induced by electromagnetic pulse (EMP) and to provide experimental evidence for the development of EMP standard and medical application. Methods The EMP simulator was used. The field strength was 200kv / m, the number of pulses was 200 and the pulse interval was 2s. Fifty-four female Sprague-Dawley rats were randomly divided into 7 groups, including 12 in the control group and 12 h after irradiation, and 6 in the remaining group (immediately after irradiation, 6, 24, 36 and 48 h). The rats were observed immediately after the light, 6,12,24,36 and 48h, the use of lanthanum nitrate tracer and transmission electron microscopy changes in myocardial ID structure. At 12h after irradiation, the changes of Zo-1 and Cx40 protein expression in myocardium were observed by immunofluorescence staining and confocal microscopy. Results In the normal control group, the myocardium of the rats was intact, the muscle segments were clear, the myofilaments were arranged neatly, the cell connection structure was intact, and the lanthanum particles deposition was close to the ID connection. The myocardial ID gap widened immediately after irradiation was not obvious, only a small amount of lanthanum particles were seen in the gap. The myocardial ID gap widened most obviously after 12h irradiation, while the ID gap was filled with a large amount of lanthanum particles. Compared with the 12h group, the group improved significantly, 48h after irradiation, the group returned to normal. At 12h after irradiation, the expression of Zo-1 and Cx43 at the junction of cardiomyocytes in the control group and the control group were both decreased. However, the mean fluorescence intensity of the two proteins in the irradiation group tended to decrease with no shift expression. Conclusion EMP irradiation can induce widening of ID gap and decrease of expression of Zo-1 and Cx43 protein in myocardium.