Effects Of EMP On Morphology Of Rat's Myocardial Intercalated Discs And Its Possible Mechanism

Electromagnetic pulse (EMP) is produced from EMP simulator. It can also be generated from other nonnuclear conditions, It possess of extremely high peak E-field , square pulse short , and pulse width , These special characteristics can damage health of people. So concerns about its bioeffects and possible health hazards to personnel have raised. The word to think highly of biological effect of EMP, there are many literature available about it . The data from our department indicate that exposure to EMP has effects on morphology and function of nervous,endocrine, cardiovascular,immune system, such as the permeability of Blood-Brain Barrier, emotion, electroencephalogram, the ability of learning and on the free radical. In this study, SD rats were used to investigate deeply the effects of EMP on intercalated discs of the cardiac musclec.OBJECTIVE: To explore the law and mechanism of intercalated discs(ID)caused by EMP radiation, so as to provide experimental basis for formulating the sanitary standard and its application to medicine.METHODS:EMP was provided by the EMP simulator of our department, the parameter is as following: 3ns rise time; 340ns pulses width; 2s pulse interval; 400,200,100 and 50 kV/m field intensity; 400,200, 100,50 and 5 pulses altogether. Male SD Rats were used,in present study.1. Male SD rats were subjected to EMP with 200 pulses and 200 kV/m field intensity in a tapered parallel plate GTEM cell. At 12h after EMP exposure, the lanthanum nitrate tracer method and the transmission electron microscope were used to observe the structural changes of left ventricular myocardium of the rats.2. Male SD rats were subjected to EMP with different field intensity in a tapered parallel plate GTEM cell. At 12h after 200 pulse , the lanthanum nitrate tracer method were used to observe the structural changes of left ventricular myocardium of the rats.3. Male SD rats were subjected to EMP with different pulses in a tapered parallel plate GTEM cell. At 12h after 200 kV/m field intensity , the lanthanum nitrate tracer method and the transmission electron microscope were used to observe the structural changes of left ventricular myocardium of the rats.4. At different time points(0,6,12,24,36,and 48h) after EMP exposure, male SD rats were subjected to EMP with 200 pulses and 200 kV/m field in a tapered parallel plate GTEM cell. the lanthanum nitrate tracer method were used to observe the structural changes of left ventricular myocardium of the rats.5. Male SD rats were subjected to EMP in a tapered parallel plate GTEM cell. At 12h after 200 kV/m and 200 pulse , the lanthanum nitrate tracer method were used to observe the structural changes of every locationof the rats ID of cardiac muscle6. After 50 kV/m,100kV/m, 200kV/m,400kV/m and 200 pulse , cardiac muscle cells was measured by FTIR and EMP's damage effect was detected as well. 7. After 200kV/m and 200 pulses, The specific resistance of cardiac muscle cells was measured by electric resistance meter.8.Lucifer yellow CH can pass through GJ to neighboring cells,but not through cell membrane.On the basis of it,we examined the change of the gap junctional intercellular communication in the different groups.The effects of HT and RES on the communication were studied.RESULTS:1.There were no changes in cardiac mnscle of the control group,After 200 kV∕m and 200 pulses EMP exposure, there were many lanthanum nitrate like linetype or waves.2. There were no obvious changes in cardiac muscle of the rats after EMP exposure . At 50 kV∕m and 100 kV∕m ,there were a few of lanthanum nitrate in cardiac mnscle of the rats. The change in ID of cardiac muscle at 200kV∕m were fewer than at 400 kV∕m after the exposure. there were many lanthanum nitrate. At 400kV∕m, the change in ID of cardiac muscle were most obvious after the exposure ,there were a lot of lanthanum nitrate .3. After 5～400 pulses EMP exposure, There were no obvious changes in cardiac muscle of the rats after exposure to EMP. After 5 pulses , there were a few of lanthanum nitrate in cardiac muscle of the rats. The change in ID of cardiac muscle were most obvious after 100 and 200 pulses exposure ,there were a lot of lanthanum nitrate. The change in ID of cardiac muscle in 50 pulses group were fewer than at other 100 and 200 pulses group. there were few of lanthanum nitrate after at 400 pulses, the damge recovered gradully.4. There were no obvious changes in cardiac muscle of the rats after EMP radiation. The change were most obvious and there were a lot of lanthanum nitrate. at 12 h after radiation , It recovered gradually at 24h after exposure. It almost became normal at the control group at 48h after exposure.5. In the right atrium and right ventricle, there were few of lanthanum nitrate of cardiac muscle.It changed significantly in ID of left ventricle, the gap augumented significantly and there were a few of lanthanum nitrate in the left atrium and left ventricle.6. After EMP exposure, the peak values for the cells of the irradiated group lower than those of the control group, which suggested that some damge effects on cardiac muscle cell induced by EMP .7.Before EMP exposure,There was no change between of experimentation group and control group,There was statistics disparation of the interaction of the time of past-irradiation and EMP,s interaction of the resistivity of cardiac muscle cell. compared to control group,The specific resistance of the irradiance group reduced from 0-36h after exposure. The specific resistance of cardiac muscle cell is recovered in an raising tendency. At 48h,8. Normally,the fluorescence can be seen beyond the fourth row cells,As a positive control,1-HT could obstruct significantly the gap junctional intercellular communication, and the dye was not transferred.After EMP exposure,the dye was only transferred to second neighboring cells,The RES could safeguard the gap junctional to abute the damage induced by EMP at some extends, and the dye was transferred to third neighboring cells.CONCLUSION:1. Tracer method is a availabe method to observe the changes of ID.2. After 50～400 kV∕m, 200 pulses EMP exposure the gap between intercalated discs became augmented along with the field intensity increasing.3. After 200 kV∕m EMP exposure the width between intercalated discs was augumented along with 5～200 pulses increasing,But the changes in ID of cardiac muscle was lower after 400 pulses.4. After 200 kV∕m, 200 pulses EMP exposure the width of gap between intercalated discs changed during 0～48h after exposure. Especially,the width of gap were rasing obviously at 12h and 24h . The changes in ID of cardiac muscle have reversibility. The changes in ID of left artrium were obviously.5. After 200 kV∕m, 200 pulses EMP exposure,configuration of cardiac muscle cell'sprotein amideⅠ,amideⅡ,deoxyribonucleic acid,lipide numerator changed and the specific rescstance between the cardial muscle cells decreased,the gap junctional conmunication reduced,and RES could relieve the damge of GJ induced by EMP exposure.