摘要
目的:一定量的电磁辐射可引起中枢神经系统神经元的损伤,但其对小胶质细胞的影响尚不清楚。实验观察电磁辐射对小胶质细胞活化状态以及分泌功能的影响,揭示电磁辐射对小胶质细胞及中枢神经损伤的效应关系。方法:实验于2006-08/2007-05在解放军第三军医大学电磁辐射医学防护教育部重点实验室完成。取体外培养的N9小胶质细胞接受X波段脉冲波,平均功率密度为90mW/cm2的电磁波,一次性照射20min,在辐照后0,1,3,6,12,24h等6个时相点观察活化的N9细胞形态学,采用免疫组化的方法观察OX-42的表达情况,用酶联兔疫吸附测定方法检测N9细胞培养上清液中肿瘤坏死因子α的水平,采用硝酸还原酶法检测培养上清液中NO浓度。以未接受电磁波辐照的N9小胶质细胞为假辐照组进行对照。结果:①电磁辐射后3hN9小胶质细胞OX-42表达开始明显增强,并一直持续到辐照后24h,细胞形态由静息状态转变为激活状态;②NO的浓度在辐照后1h开始升高(P<0.05),到辐照后6h达到峰值(P<0.01),12h后趋于恢复,24h后再次明显升高(P<0.05)。③肿瘤坏死因子α水平辐照3h后显著升高(P<0.01),并一直持续到12h,到辐射后24h又再次升高,并达到峰值(P<0.01)。结论:电磁辐射辐照可明显诱导小胶质细胞激活,活化后的小胶质细胞分泌NO、肿瘤坏死因子α等细胞因子的功能增强,分泌大量细胞因子反馈调节引起辐射后期的小胶质细胞激活。
AIM： Electromagnetic field （EMF） radiation at a certain dose can induce central nervous system （CNS） injury, however its effect on microglia is unclear. This study was designed to investigate the effect of EMF radiation on the activation and secretion of microglia in CNS.
METHODS： The experiment was carried out in the Key Laboratory for Electromagnetic Radiation Medical Protection by the State Ministry of Education, the Third Military Medical University of Chinese PLA from August 2006 to May 2007. The in vitro cultured N9 microglias were exposed to X-band pulse wave with the mean power density of 90 mW/cm2 EMF. The expression of OX-42 was assessed by immunohistochemistry at six time points （0, 1, 3, 6, 12, 24 hours） after 20-minute radiation. Tumor necrosis factor （TNF）-α level in the supernatant of N9 cell medium was detected by enzyme linked immunosorbent assay. NO concentration in supernatant was determined by the method of nitrate reductase. N9 microglias without EMF radiation were served as controls.
RESULTS： ①EMF radiation significantly upregulated OX-42 expression in N9 cells at 3 hours after radiation. The higher expression of OX-42 persisted at 24 hours. The modality of N9 cells changed into activated. ②The concentration of NO was increased at 1 hour after EMF radiation （P〈 0.05）, peaked at 6 hours （P〈 0.01） and recovered as 12 hours. And another peak value of NO concentration appeared at 24 hours （P 〈 0.05）. ③The level of TNF-α was increased at 3 hours and sustained to 12 hours after EMF radiation, it was increased significantly at 24 hours again （P〈 0.01）.
CONCLUSION： EMF radiation can induce microglia activation. The No and TNF-α secretions of activated microglia increase after EMF radiation, and the feedback regulation of cytokines from microglia may result in the activation of microglia at the later stage of radiation.
出处
《中国组织工程研究与临床康复》
CAS
CSCD
北大核心
2007年第44期8916-8919,共4页
Journal of Clinical Rehabilitative Tissue Engineering Research
基金
国家自然科学基金资助项目(30470418)~~
