【摘要】：影響電磁輻射健康效應(yīng)的主要參數(shù)包括頻率和強(qiáng)度。不同頻率的電磁波來源、用途不同,其健康效應(yīng)也不盡相同。微波(300MHz-300GHz)電磁輻射屬于非電離輻射,900MHz是國際通用的民用無線通訊頻段。高強(qiáng)度微波電磁輻射(EMR)通過“致熱效應(yīng)”引起機(jī)體的健康危害已經(jīng)得到有關(guān)研究的證實(shí),而低強(qiáng)度微波輻射,尤其是900MHz微波電磁輻射,長期暴露的健康效應(yīng)及其機(jī)理目前尚有爭議。國際上關(guān)于微波電磁輻射的研究焦點(diǎn)主要是對中樞神經(jīng)系統(tǒng)(CNS)腫瘤和行為功能影響的研究,流行病學(xué)調(diào)查表明,電磁輻射的過量接觸可導(dǎo)致中樞神經(jīng)系統(tǒng)和植物神經(jīng)功能紊亂,且動(dòng)物實(shí)驗(yàn)表明,電磁輻射可以引起學(xué)習(xí)記憶及認(rèn)知能力障礙。 為了進(jìn)一步探討900MHz微波電磁輻射對中樞神經(jīng)系統(tǒng)功能影響及其作用機(jī)理,本實(shí)驗(yàn)選用2000μW/cm2的輻射強(qiáng)度,采用體內(nèi)動(dòng)物實(shí)驗(yàn)及體外原代神經(jīng)元細(xì)胞培養(yǎng)的方法,從突觸結(jié)構(gòu)可塑性(腦區(qū)突觸數(shù)目和結(jié)構(gòu)的改變等)和功能可塑性(神經(jīng)元和突觸部位的某些受體的變化)兩方面入手,探討電磁輻射對學(xué)習(xí)記憶影響的機(jī)制。 第一部分EMR后對大鼠學(xué)習(xí)記憶功能的影響及組織病理學(xué)觀察 目的： 探討2000μW/cm2電磁輻射對大鼠學(xué)習(xí)記憶功能的影響。 方法： 實(shí)驗(yàn)分為空白對照組,假輻射組,1h/d、2h/d、3h/d輻射組。將輻射組大鼠固定體位,頭部接受功率密度為2000μW/cm2的近場輻射,連續(xù)輻射30d。通過Morris水迷宮檢測大鼠的學(xué)習(xí)記憶能力,采用硫堇染色法觀察大鼠海馬組織結(jié)構(gòu)的變化。 結(jié)果： 1行為學(xué)檢測結(jié)果表明,假輻射組大鼠各項(xiàng)指標(biāo)與空白對照組相比均無明顯變化(P0.05)；而各輻射組大鼠的逃避潛伏期較空白對照組明顯延長(P0.05),在空間探索實(shí)驗(yàn)中各輻射組大鼠的空間探索次數(shù)明顯減少(P0.05)。 2形態(tài)學(xué)檢測結(jié)果表明,假輻射組海馬神經(jīng)元形態(tài)與數(shù)目與空白對照組相比均無明顯差異；而輻射組大鼠海馬CA1區(qū)神經(jīng)細(xì)胞數(shù)量顯著減少(P0.05),且細(xì)胞排列紊亂,胞漿尼氏體明顯減少,細(xì)胞核固縮。 結(jié)論： 2000μW/cm2電磁輻射可導(dǎo)致大鼠學(xué)習(xí)記憶功能下降,其機(jī)制可能與損傷大鼠海馬神經(jīng)元有關(guān)。 第二部分EMR對大鼠海馬超微結(jié)構(gòu)及凋亡相關(guān)因子表達(dá)的影響 目的： 探討2000μW/cm2電磁輻射對大鼠海馬神經(jīng)元超微結(jié)構(gòu)及凋亡相關(guān)因子表達(dá)的影響。 方法： 實(shí)驗(yàn)分為空白對照組,假輻射組,1h/d、2h/d、3h/d輻射組。將輻射組大鼠固定體位,頭部接受功率密度為2000μW/cm2的近場輻射,連續(xù)輻射30d。通過透射電鏡觀察海馬超微結(jié)構(gòu)改變,采用免疫組織化學(xué)法檢測大鼠海馬組織Bcl-2、Bax的表達(dá)變化,Western blotting法檢測海馬組織Caspase-3蛋白的表達(dá)變化。 結(jié)果： 輻射組海馬細(xì)胞核仁消失,染色質(zhì)呈顆粒、塊狀凝集在核膜下,電子密度高,核內(nèi)出現(xiàn)透明區(qū)等早期凋亡征象,突觸界面結(jié)構(gòu)出現(xiàn)明顯病理性改變；與空白對照組比較,輻射組大鼠海馬組織Bax、Caspase-3蛋白表達(dá)升高(P0.05),Bcl-2蛋白表達(dá)降低,Bax/Bcl-2比值顯著升高(P0.05)。 結(jié)論： 電磁輻射可引起海馬神經(jīng)元細(xì)胞損傷和凋亡,而機(jī)制可能與凋亡相關(guān)因子Bcl-2、Bax、Caspase-3表達(dá)變化相關(guān)。 第三部分EMR對大鼠海馬腦區(qū)NMDA受體蛋白及其mRNA表達(dá)的影響 目的： 探討2000μW/cm2電磁輻射對大鼠海馬(?)NMDA(NR1、NR2A和NR2B)受體蛋白及其mRNA水平表達(dá)的影響,揭示電磁輻射對大鼠學(xué)習(xí)記憶功能的損傷機(jī)制。 方法： 實(shí)驗(yàn)分為空白對照組,假輻射組,1h/d、2h/d、3h/d輻射組。將輻射組大鼠固定體位,頭部接受功率密度為2000μW/cm2的近場輻射,連續(xù)輻射30d。采用免疫組化法和Western blotting法檢測大鼠海馬組織NMDA (NR1、NR2A和NR2B)受體蛋白表達(dá)的變化,RT-PCR法檢測大鼠海馬組織NMDA (NR1、NR2A和NR2B)mRNA表達(dá)的變化。 結(jié)果： 各輻射組大鼠海馬神經(jīng)元排列紊亂,NMDA (NR1、NR2A和NR2B)陽性細(xì)胞比率顯著下降,海馬組織NMDA (NR1、NR2A和NR2B)蛋白及其mRNA表達(dá)水平明顯降低(P0.05)。 結(jié)論： 2000μW/cm2電磁輻射可導(dǎo)致大鼠學(xué)習(xí)記憶功能下降,其機(jī)制可能與大鼠海馬組織NMDA (NR1、NR2A和NR2B)蛋白及其mRNA的表達(dá)降低有關(guān)。 第四部分EMR致海馬神經(jīng)細(xì)胞CREB和CaMKⅡ表達(dá)的影響 目的： 探討2000μW/cm2電磁輻射對原代培養(yǎng)海馬神經(jīng)元細(xì)胞CREB、 CaMKⅡ表達(dá)的影響,揭示電磁輻射對大鼠海馬神經(jīng)細(xì)胞的損傷機(jī)制。 方法： 取原代培養(yǎng)7d的大鼠海馬神經(jīng)元,隨機(jī)分為5組：分為空白對照組,假輻射組,1h/d、2h/d、3h/d輻射組。將輻射組海馬神經(jīng)細(xì)胞接受功率密度為2000μW/cm2的近場輻射,連續(xù)輻射5d。通過倒置顯微鏡觀察海馬神經(jīng)元形態(tài)變化,MTT法檢測神經(jīng)元細(xì)胞活力,采用Western blotting法檢測大鼠海馬神經(jīng)細(xì)胞CREB和CaMKII蛋白表達(dá)的變化,RT-PCR法檢測大鼠海馬神經(jīng)細(xì)胞CREB和CaMKII mRNA表達(dá)的變化。 結(jié)果： 正常對照組大鼠海馬神經(jīng)元核規(guī)整,細(xì)胞突起明顯；輻射組大鼠海馬神經(jīng)元核皺縮、突起回縮、變性。假輻射組大鼠各項(xiàng)指標(biāo)與空白對照組相比均無顯著差異(P0.05)；而各輻射組大鼠海馬神經(jīng)元細(xì)胞活力明顯下降(P0.05)；CREB和CaMKⅡ蛋白及其mRNA表達(dá)水平明顯降低(P0.05)。 結(jié)論： 2000μW/cm2電磁輻射致大鼠海馬神經(jīng)細(xì)胞損傷機(jī)制可能與CREB和CaMKⅡ蛋白及其mRNA的表達(dá)降低有關(guān)。
[Abstract]:The main parameters affecting the health effects of electromagnetic radiation include frequency and intensity. Different sources and uses of electromagnetic waves have different health effects. Microwave (300MHz-300GHz) electromagnetic radiation belongs to non-ionizing radiation, 900MHz is the international common civil wireless communication frequency band. High intensity microwave electromagnetic radiation (EMR) passes through "heating effect". "The health hazards caused by microwave radiation, especially 900MHz microwave electromagnetic radiation, have been confirmed by relevant studies. The long-term health effects and their mechanisms of exposure to microwave electromagnetic radiation are still controversial. Epidemiological studies have shown that excessive exposure to electromagnetic radiation can lead to functional disorders of the central nervous system and autonomic nervous system, and animal experiments have shown that electromagnetic radiation can cause learning and memory and cognitive impairment.
In order to further explore the effect of 900MHz microwave electromagnetic radiation on the function of the central nervous system and its mechanism, we used the radiation intensity of 2000 mu W/cm 2 to study the plasticity of synaptic structure (the number and structure of synapses in the brain area, etc.) and functional plasticity (neural plasticity) by in vivo animal experiment and in vitro primary culture of neurons. The mechanism of the effect of electromagnetic radiation on learning and memory was discussed.
Part one the effect of EMR on learning and memory in rats and its histopathological observation.
Objective:
Objective to investigate the effect of 2000 W/cm2 electromagnetic radiation on learning and memory function in rats.
Method:
The rats in the radiation group were placed in a fixed position and received near-field radiation with a power density of 2000 mu W/cm2 for 30 days. The learning and memory abilities of the rats were measured by Morris water maze, and the hippocampal tissues were observed by thionine staining.
Result:
The results of behavioral tests showed that there were no significant changes in the indexes of rats in the sham radiation group compared with the blank control group (P 0.05), but the escape latency of rats in each radiation group was significantly longer than that in the blank control group (P 0.05), and the number of space explorations in each radiation group was significantly reduced (P 0.05).
The results of morphological examination showed that there was no significant difference in the morphology and number of hippocampal neurons between the sham radiation group and the blank control group, but the number of neurons in the CA1 area of the hippocampus in the radiation group was significantly reduced (P 0.05), and the cell arrangement was disordered, the cytoplasmic Nissl body was significantly reduced, and the nucleus was condensed.
Conclusion:
2 000 mu W/cm 2 electromagnetic radiation can lead to the decline of learning and memory function in rats, which may be related to the damage of hippocampal neurons.
The second part is the effect of EMR on the ultrastructure of hippocampus and the expression of apoptosis related factors in rats.
Objective:
Objective To investigate the effects of 2 000 mu W/cm 2 electromagnetic radiation on ultrastructure and expression of apoptosis-related factors in hippocampal neurons of rats.
Method:
The experiment was divided into three groups: control group, sham radiation group, 1h/d, 2h/d, 3h/d radiation group. The rats in radiation group were fixed in position and received near-field radiation with a power density of 2000 mu W/cm 2 for 30 days. Blotting method was used to detect the expression of Caspase-3 protein in hippocampus.
Result:
In radiation group, nucleolus disappeared, chromatin was granular, mass agglutinated in the subnuclear membrane, high electron density, transparent area appeared in the nucleus and other early signs of apoptosis, synaptic interface structure showed obvious pathological changes; compared with the blank control group, the expression of Bax, Caspase-3 protein in the hippocampus of radiation group increased (P 0.05), and the expression of Bcl-2 protein decreased (P 0.05). The Bax/Bcl-2 ratio increased significantly (P0.05).
Conclusion:
Electromagnetic radiation can induce injury and apoptosis of hippocampal neurons, and the mechanism may be related to the expression of apoptosis-related factors Bcl-2, Bax and Caspase-3.
The third part is the effect of EMR on the expression of NMDA receptor protein and mRNA in rat hippocampus.
Objective:
Objective To investigate the effects of 2 000 mu W/cm 2 electromagnetic radiation on the expression of (?) NMDA (NR1, NR2A and NR2B) receptor protein and its mRNA in rat hippocampus, and to reveal the mechanism of learning and memory impairment induced by electromagnetic radiation.
Method:
The experiment was divided into three groups: control group, sham radiation group, 1h/d, 2h/d, 3h/d radiation group. The rats in radiation group were fixed in position and received near-field radiation with a power density of 2000 mu W/cm2 for 30 days. The expression of NMDA (NR1, NR2A and NR2B) receptors in hippocampus was detected by immunohistochemistry and Western blotting, and RT-PCR. Changes of NMDA (NR1, NR2A and NR2B) mRNA expression in rat hippocampus.
Result:
The distribution of hippocampal neurons was disordered, the ratio of NMDA (NR1, NR2A and NR2B) positive cells decreased significantly, and the expression levels of NMDA (NR1, NR2A and NR2B) protein and its mRNA in hippocampus decreased significantly (P 0.05).
Conclusion:
2000 mu W/cm2 electromagnetic radiation can induce the decline of learning and memory function in rats. The mechanism may be related to the decrease of NMDA (NR1, NR2A and NR2B) protein and its mRNA expression in rat hippocampus.
The fourth part is the effect of EMR on the expression of CREB and CaMK II in hippocampal neurons.
Objective:
Objective To investigate the effect of 2 000 mu W/cm 2 electromagnetic radiation on the expression of CREB and CaMK II in primary cultured hippocampal neurons and to reveal the mechanism of injury of electromagnetic radiation on hippocampal neurons in rats.
Method:
The primary cultured hippocampal neurons were randomly divided into five groups: blank control group, sham radiation group, 1h/d, 2h/d, 3h/d radiation group. Western blotting was used to detect the expression of CREB and CaMKII protein in rat hippocampal neurons. RT-PCR was used to detect the expression of CREB and CaMKII mRNA in rat hippocampal neurons.
Result:
In the normal control group, the hippocampal neurons had regular nuclei and distinct cellular processes; in the irradiated group, the hippocampal neurons had shrinkage, retraction and degeneration; there was no significant difference in all the indexes between the sham-irradiated group and the blank control group (P 0.05); however, the activity of the hippocampal neurons in the irradiated groups decreased significantly (P 0.05); the CREB and CaMK II proteins in the irradiated group were And the expression level of mRNA decreased significantly (P0.05).
Conclusion:
The injury mechanism of hippocampal neurons induced by 2 000 mu W/cm 2 electromagnetic radiation may be related to the decrease of CRB and CaMK II protein and its mRNA expression.
【學(xué)位授予單位】：承德醫(yī)學(xué)院
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2011
【分類號】：R363

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