摘要
目的 :研究电磁脉冲 (EMP)辐照对动物记忆力影响并探讨其作用机制。方法 :①行为实验 :用穿梭箱训练成年大鼠 ,使之形成条件反射 ,采用高场强EMP(6× 10 4 V/m)进行照射 ,并于照后即刻 ,3h ,6h ,12h ,2 4h分别进行测试 ,观察其对记忆保持能力的影响 ;②照射后大鼠活杀取脑 ,HE和神经元尼氏体染色 ,组织形态学观察 ;③海马神经元原代培养 ,经EMP辐照后观察形态改变 ,并采用流式细胞仪检测其凋亡情况。结果 :照射后即刻大鼠的主动回避反应减少 ,而被动逃避反应增多 ,与照射前相比有非常显著性差异 (P <0 .0 1) ,3h后渐趋照前水平 ;照射前后大鼠对刺激做出反应的潜伏期无统计学差异 (P >0 .0 5 )。EMP照射可造成海马组织和培养神经元的变性、凋亡、坏死及血液循环障碍等病理改变。结论 :EMP照射可迅速造成实验大鼠暂时的记忆力下降 ,使海马组织细胞损伤及其凋亡增加 ,上述改变可能是EMP致脑功能障碍的病理学基础之一。
Objective:To investigate the effects of electromagnetic pulse (EMP) on defensive conditioned reflex of rats and to explore the mechanisms responsible for the effects through observing the lesion of brain tissues induced by EMP exposure.Methods:①Behavioral test: at first,fifteen adult Wistar rats were trained 40 times/day for 10 successive days with two-way active-avoidance(AV) shuttle box.Eleven rats which got over 80% correct active avoidance response in the task were selected for exposure to high field strength EMP irradiation (6×10 4V/m,rise time 20?ns,pulse width 30?μs,5 pulses in 2 minutes).Then repeated measurement was taken with shuttle box at different time points after exposure.The scores of each rat′s performance in different phases were collected for statistical analysis.②Morphological observation of hippocampus tissues: after EMP exposure,ten rats were sacrificed and brain tissues were taken to prepare paraffin-imbedded sections. The sections were stained with hematoxylin-eosin(H-E) and toluidine blue(TB) respectively for light microscopic examination.③Culture of primary hippocampus neuron: hippocampus neurons were isolated from rat brain tissues of the neonates and cultured for about 10 days.The mature cells were exposed to EMP irradiation.Pathologic changes were observed under inverted phase contrast microscope and the cell apoptosis ratio was measured with flow cytometer.Results:In behavioral test,it was found that all the rats examined possessed a significantly lower AV value immediately after exposure as compared with that before radiation(F= 19.20, P< 0.01),then it tended to recover at 3h after exposure; contrarily,escape(ESC) rose markedly after exposure as compared with that before exposure(F=14.49, P<0.01) and tended to recover at 3?h after exposure as well.There were no differences in AV latency(AVLAT) and ESC latency(ESCLAT) value before and after irradiation(F=0.93 and 1.04,respectively, P>0.05).Morphological changes were found in different regions of brain, especially in hippocampus.After EMP exposure, cultured cells took on a higher refractive power.Liquefaction of neuron could be seen. The recoiled,degenerative neurite looked like beads.Neuropil fragmentated and became sparse gradually. The results of flow cytometry test: in the 2 hours after exposure, the percentage of apoptosis of exposed cells was 31.37% which was significantly higher than that of sham-exposure cells(0.02%).Conclusion:EMP irradiation may result in a temporary loss of acquired conditioned reflex in rats,which exhibited declining of response correctness ratio,but the effects disappeared after a short period of time;AVLAT and ESCLAT of rats in the behavioral test were not influenced by EMP irradiation. Damages such as cell degeneration,apoptosis,necrosis and blood circulatory disorder could be seen in hippocampus tissues and ex vivo cultured neurons after EMP irradiation.
出处
《军事医学科学院院刊》
CSCD
北大核心
2003年第5期356-359,共4页
Bulletin of the Academy of Military Medical Sciences
基金
全军指令性课题 (0 1L0 2 3)
关键词
电磁脉冲
记忆
影响
机制
辐射
条件反射
海马
radiation
electromagnetic pulse
conditioned reflex
memory
hippocampus
