【作者】 贾丽；

【导师】 翟国庆；

【作者基本信息】 浙江大学 ， 环境科学， 2010， 硕士

【摘要】 为定量研究实验室可控条件下,机场噪声生理效应影响,对杭州市萧山国际机场不同机型飞机起降噪声进行采样,按照航班时刻及对应机型进行编排并调整其一个飞行周期内计权等效连续感觉噪声级(L_WECPN)为75±1.0dB和80±1.0dB,作为实验暴露声源。选取与人类中枢神经系统较为相近的Sprague Dawley大鼠作为实验对象,使用国际上常用的动物焦虑模型——旷场反应箱和高架十字迷宫考察大鼠神经行为,大鼠眼眶后静脉丛采血后利用高效液相色谱-荧光法测定大鼠血浆神经递质（去甲肾上腺素和5-羟色胺）含量,同时利用透射电镜观察大鼠中枢神经系统海马区和颞叶区的神经组织形态。相同暴露时间条件下,实验组大鼠旷场反应实验中央格停留时间延长,跨格数减少,与对照组差异显著（P＜0.05）;高架十字迷宫实验中实验组大鼠进入开放臂次数所占百分数和开放臂停留时间所占百分数均显著低于对照组（P＜0.05）。实验Ⅱ组(L_WECPN为80±1.0dB)与对照组之间的差异性比实验Ⅰ组(L_WECPN为75±1.0dB)显著。结果表明机场噪声暴露对大鼠的认知能力、探索行为及兴奋性、运动活力均产生了一定影响,影响程度与噪声暴露强度相关,强度越高,对大鼠神经行为的影响越大。神经递质测定结果显示,噪声暴露时间少于36d时,实验Ⅰ组大鼠血浆神经递质含量变化趋势与对照组较为一致,无显著性差异（P＞0.05）,持续暴露过程中,该组大鼠血浆5-HT浓度不断下降,暴露96d后明显低于对照组（P＜0.05）。整个实验周期中,实验Ⅱ组大鼠血浆NE和5-HT浓度随时间延长呈先上升后下降趋势。NE浓度在噪声暴露15d后达到最大值,与对照组差异显著（P＜0.05）,5-HT浓度在暴露8d后达到最大值（P＜0.05）,随后浓度开始下降,暴露96d后,两者浓度均显著低于对照组（P＜0.05）,结果表明中短期噪声暴露（＜15d）可导致大鼠产生焦虑症状,而长期暴露（＞30d）则会使大鼠产生抑郁症状或抑郁和焦虑合病症状。恢复过程中,实验组大鼠在安静状态下恢复60d后,血浆神经递质含量与对照组相比无显著性差异,表明大鼠在噪声暴露条件下受到损伤的交感神经系统得到了一定程度的恢复。观察大鼠神经组织形态后发现,噪声暴露60d后,对照组颞叶区神经元细胞正常,海马区和颞叶区突触间隙清楚,突触前驱有线粒体和突触小泡;实验Ⅱ组颞叶神经元细胞凋亡,突触形态发生改变,间隙模糊,染色质聚合,突触小泡不清晰。结果表明长期机场噪声暴露会对机体神经行为及功能产生不利影响。更多还原

【Abstract】 In order to investigate the physiological effects of aircraft noise under the condition of laboratory, taking off and landing noise emitted from various aircrafts of Hang-zhou Xiao-shan International Airport were sampled as the exposure noise source. The aircraft noise was arranged according to flight schedule and aircrafts kinds, and its weighted equivalent continuous perceive noise level (L_WECPN) was adjusted to 75±1.0dB and 80±1.0dB. Sprague-Dawley rats whose central nervous system are similar to humans’ were selected as the experiment subjects. Behaviors of rats were tested through the commonly used animal anxiety models-open field and plus-maze, concentration of plasma neurotransmitters （Norepinephrine, NE and 5-hydroxytryptamine, 5-HT） was determined with the High Performance Liquid Chromatography-Fluorimetric, and the morphology of nerve tissues in hippocampus and temporal lobe was observed by Transmission Electron Microscopy.Within the same exposure time, the rats which were exposed to aircraft noise spent more time in the central part of the open field, but showed less locomotion, and had significant differences compared with control group （P<0.05）; in the plus-maze test, the percent of open arm entry times and open arm time of experimental group was lower than control group （P<0.05） significantly. In addition, the differences between experimental group II (L_WECPN 80±1.0dB) and control group were more prominent than experimental group I (L_WECPN 75±1.0dB). Results indicated that aircraft noise had negative effects on cognitive abilities, exploratory behaviours, excitabilities and loccmotor activities of rats.The results of neurotransmitters showed that, when noise exposure time was lower than 36 days, the plasma neurotransmitters change current of experimental group I was consistent of control group and there was no significant difference between two groups（P>0.05）. In the sustaining exposure process, neurotransmitters concentration of this group decreased gradually, and when the noise exposure lasted for 96 days, concentration of 5-HT was lower than control group significantly（P<0.05）. In the whole experient process, NE and 5-HT concentration of experimental group II increased at the begining, then decreased with the time. NE concentration reached the maximum on the 15th day, and showed significant differences compared with control group （P<0.05）; 5-HT concentration reached the maximum on the 8th day（P<0.05）. When noise exposure lasted for 96 days, NE and 5-HT concentration were both lower than control group significantly （P<0.05）. Results indicated that medium and short term noise exposure （<15d） could produce anxiety on rats, however, long term noise exposure （>30d） could produce depression or comorbid anxiety and depression on rats. In the recovery stage, plasma neurotransmitters of experimental group showed no significant differences compared with control group after 60days（P<0.05）, which indicated that the damaged sympathetic nervous of rats who exposed to noise recovered gradually in quiet environment.From the morphology of nerve tissues results, we can see that when noise exposure time lasted for 60 days, neurons of temporal lobe of control group were normal, synaptic cleft of hippocampus and temporal lobe area was clear, and there were mitochondria and synaptic vesicles in synaptic precursor. However, the neurons of temporal lobe of experimental group II began to apoptosis, synapse morphology had changed, synaptic cleft of hippocampus and the temporal lobe area was vague, chromatin aggregated and synaptic vesicles was not clear. Results showed that long term aircraft noise exposure would have negative effects on rats’ neurobehaviorals and functions.更多还原