高功率微波辐照对大鼠免疫组织基因表达的影响

Effect of high power microwave on gene expression of immune tissues in rats

目的:观察高功率微波辐照大鼠致淋巴结、胸腺基因表达谱改变情况,探讨电磁辐射非热效应分子作用。方法:微波接触剂量现场检测于2002-01/2005-05进行;高功率微波对大鼠免疫组织基因表达的影响实验于2003-12/2005-05分别在航天中心医院动物实验室和军事医学科学院放射与辐射医学研究所免疫学研究室完成。①采用德国Narda公司EMR射频电磁辐射分析仪,根据国家作业场所微波辐射卫生标准(GB10436-89)测定和评价该研究所近年(2002/2005)作业人员操作位的微波辐射强度,同时收集该所既往微波现场检测资料。②应用由上海沪晶生物科技有限公司生产的10003个基因的大鼠基因表达谱芯片(SBC-R-RC-100-10)检测10mW/cm2重复照射Wistar大鼠150min后1,3,7,14d的淋巴结、胸腺的基因表达谱改变情况。健康二级成年雄性Wistar大鼠34只,随机分为未照射对照(10只)和平均功率密度10mW/cm2照射(24只)2个组,重复照射150min(照射30min/d,连续照射5d),峰值功率为16W/cm2,屏蔽室内温度约28℃,相对湿度24%。结果:实验大鼠34只均进入结果分析。①10mW/cm2微波一次照射Wistar大鼠30min,不会引起大鼠直肠温度明显升高。②照射后各时间点淋巴结差异表达基因数量均多于胸腺。淋巴结、胸腺差异表达基因数:照后1d分别为913和156个,照后3d为157和88个,照后7d为97和37个,照后14d为208和148个。③10mW/cm2功率密度微波连续5d照射Wistar大鼠共150min,能够引起实验大鼠淋巴结和胸腺组织基因表达变化。差异表达基因涉及信号转导、免疫及防御反应、氧化应激、凋亡、细胞周期、细胞黏附、细胞骨架组建和发生、DNA复制与修复等生物学功能。④在这些已知生物学功能基因中信号转导相关差异表达基因数量最多(淋巴结25个,胸腺11个)。⑤淋巴结中8个氧化应激相关差异表达基因则明显地表现出功能和表达模式的一致性。它们参与的是抗氧化生物学过程,表达量均有一定程度的下调。结论:①10mW/cm2高功率微波重复照射Wistar大鼠150min对免疫组织的影响属于非热效应分子作用。②Wistar大鼠淋巴结对微波的辐照敏感性高于胸腺。③电磁辐射可能在一定程度上扰乱了动物体内氧化和抗氧化平衡。

AIM： To observe the changes of gene expression profile in lymph node and thymus of rats exposed to high power microwave （HPM）, and explore the molecular mechanism of non-thermal effects of electromagnetic fields. METHODS： The on-the-spot detection on the exposure dose of microwave was conducted from January 2002 to May 2005. The study on effect of HPM on gene expression of immune tissues in rats was performed from December 2003 to May 2005 respectively in the Animal Laboratory of Aerospace Center Hospital and the Department of Immunology in the Institute of Radiation Medicine of Academy of Military Medical Sciences. ①The EMR electromagnetic field analyzer manufactured by German Narda Corporation was used to measure and evaluate the power density of occupational exposure in recent years （2002/2005） of the institute according to the National Hygienic Standard for Microwave Radiation in the Work Environment of China （ GB 10436-89）. Meanwhile, past records of the occupational exposure were collected. ②10 003 gene expression profile arrays of rats （SBC-R-RC-100-10） that produced by Shanghai Hujing Biotech Co,. Ltd, was adopted to inspect the changes of gene expression profile in lymph node and thymus of Wistar rats, which were intermittently exposed to 10 mW/ cm^2 HPM for total 150 minutes, respectively at 1, 3, 7 and 14 days after exposure. Thirty-four second grade healthy adult Wistar rats were randomly divided into unexposed control group （n=10） and the radiation group （ exposed to 10 mW/cm2, n=24）. Rats in the radiation group were exposed intermittently for total 150 minutes （30 minutes a day for 5 continuous days） with the peak power of 16 W/cm2 and the relative humidity of 24% at 28 ℃. RESULTS： A total of 34 rats were involved in the analysis of results. ① The temperature in rectum of rats exposed to 10 mW/ cm2 HPM for 30 minutes was not significantly increased. ②The number of differentially expressed genes of lymph node at all time points was grdater than that of thymus. The number of differentially expressed genes of lymph node and thymus were as follows： they was respectively 913 and 156 at one day after exposure, and was 157 and 88 at 3 days later, 97 and 37 at 7 days later, 208 and 148 at 14 days later. ③The gene expression profile in immune tissues of lymph node and thymus in rats was changed after intermittently exposed to 10 mW/ cm2 HPM 150 minutes for 5 days. The biological processes, in which the differentially expressed genes were mainly involved, included signal transduction, immune and defense response, oxidative stress, apaptosis, cell cycle, cell adhesion, cytoskeleton organization andbiogenesis, DNA replication and repair etc.④The total number （ 36 genes, lymph node 25 and thymus 11） of the differentially expressed genes was the most in signal transduction （25 in lymph node and 11 in thymus） compared with other biological processes mentioned before. ⑤Eight genes in lymph node related to oxidative stress were obviously similar on the biological process and expression pattern, which participated in the anti-oxidative process, and the expression amount was down-regulated in some extent. CONCLUSION： ① The influence of HPM on immune tissues of rats exposed intermittently to 10 mW/cm^2 for total 150 minutes belongs to the molecular mechanism of non-thermal effects. ②The radiosensitivity of lymph node in Wistar rats is higher than that of thymus. ③The balance between oxidation and anti-oxidation system in animals is probably disturbed by electromagnetic fields to some extent.