Streptavidin包被的量子点慢性暴露对大鼠海马突触可塑性的影
发布时间：2018-08-14 11:37
【摘要】：量子点由于具卓越的理化性质,小尺寸效应、表面效应、量子尺寸效应、宏观量子隧道效应等。所以被广泛地应用在电子、光学、磁学、能源化工、生物医学、环境保护和纳米微加工技术等各大领域。但是,随着量子点的产业化进程,在不久的将来,量子点的大规模投入生产以及日益广泛应用,很有可能大大增加人们接触到并暴露在量子点的环境中的机会。因此急需展开有关量子点生物安全性及其潜在危害的研究。 多年来的研究表明,海马是学习记忆的主要部位,海马结构广泛参与了学习与记忆,而突触可塑性是学习与记忆的细胞和分子基础。所以,我们选择了大鼠海马作为切入点研究Streptavidin包被的量子点慢性暴露对输入-输出曲线(I/O)、双脉冲易化(PPF)和长时程增强(LTP)的影响。 1、0.5 nM strep-CdSe/ZnS QD慢性暴露组动物的fEPSP和PS I/O曲线与对照组无显著性差异;10 nM strep-CdSe/ZnS QD慢性暴露能够显著增强大鼠海马DG区I/O的PS幅度和fEPSP斜率的幅度,大鼠海马DG区的基础突触传递得到了增强,我们前期的工作也证实了原代培养的海马神经元中加入高浓度的量子点后,其钙离子浓度显著升高,有助于提高某些神经递质的释放和增强突触后的反应,可能导致慢性高浓度量子点暴露引起基本突触传递的增强。 2、PPF指的是当一个突触被一短暂间隔的双脉冲刺激后,第二个反应会明显强于第一个反应的现象,描述的是一种短时程突触可塑性。这个现象部分归因于第二次刺激引起的神经递质的释放量增加,另外DG区的PS的PPF源于突触后的原因比突触前的调节更为重要。在本实验中我们发现,慢性量子点暴露无论是在0.5nM浓度下暴露还是在10nM浓度下暴露都显著地降低了PPF的峰值,这说明慢性量子点暴露损伤了大鼠海马DG区的短时程突触可塑性。 3、LTP是一种典型活动依赖性的突触可塑性的电生理模型,是公认的学习与记忆活动的细胞分子生物学基础。我们的实验结果表明, 0.5 nM strep-CdSe/ZnS QD慢性量子点暴露显著降低了EPSP和PS的LTP,10 nM strep-CdSe/ZnS QD量子点慢性暴露对LTP抑制的更为严重。这说明慢性量子点暴露损伤了大鼠海马DG区长时程的突触可塑性。这种突触可塑性损伤可能与Cd~2+的释放、氧化应激等因素有关。具体机制还有待于进一步的研究。
[Abstract]:Quantum dots have excellent physical and chemical properties, small size effect, surface effect, quantum size effect, macroscopic quantum tunneling effect and so on. So it is widely used in many fields, such as electronics, optics, magnetism, energy and chemical industry, biomedicine, environmental protection and nanotechnology. However, with the industrialization of quantum dots, in the near future, the large-scale production and increasingly widespread application of quantum dots, it is likely to greatly increase people's exposure to and exposure to the environment of quantum dots. Therefore, it is urgent to study the biological safety and potential hazards of quantum dots. Over the years studies have shown that the hippocampus is the main site of learning and memory, the hippocampal structure is widely involved in learning and memory, and synaptic plasticity is the cellular and molecular basis of learning and memory. So. We selected the hippocampus of rats as a starting point to study the effects of chronic exposure to Streptavidin coated QDs on I / O curves, double pulse facilitation (PPF) and long duration enhanced (LTP). 1nM strep-CdSe/ZnS QD chronic exposure group animals were selected to study the effects of chronic exposure to QDs coated with Streptavidin on the input-output curve (I / O), double pulse facilitation (PPF) and long-term enhanced (LTP). There was no significant difference in fEPSP and PS I / O curves between the control group and the control group. Chronic exposure to 10 nm strep-CdSe/ZnS QD could significantly increase the amplitude of PS and fEPSP slope of I / O in rat hippocampal DG region. The basic synaptic transmission in rat hippocampal DG region was enhanced. Our previous work also confirmed that the calcium concentration of primary cultured hippocampal neurons increased significantly after the addition of high concentration quantum dots. To increase the release of certain neurotransmitters and enhance postsynaptic responses, PPF refers to the fact that when a synapse is stimulated by a short interval of double pulses, the second response is significantly stronger than the first. A short-term synaptic plasticity is described. This phenomenon is partly due to the increase in the release of neurotransmitters induced by the second stimulation, and the postsynaptic PPF in the DG region is more important than the pre-synaptic regulation. In this study, we found that chronic quantum dot exposure significantly reduced the peak value of PPF both at 0.5nM concentration and 10nM concentration. This suggests that chronic quantum dot exposure injures short-term synaptic plasticity in rat hippocampal DG region. 3 LTP is a typical activity dependent electrophysiological model of synaptic plasticity. It is recognized as the basis of cellular and molecular biology for learning and memory activities. Our experimental results show that the chronic QD exposure of 0.5 nm strep-CdSe/ZnS QD significantly reduces the inhibition of LTP by EPSP and PS LTP10nM strep-CdSe/ZnS QD QD QDs. This suggests that chronic quantum dot exposure injures synaptic plasticity in the long-term DG region of rat hippocampus. This synaptic plasticity may be related to the release of Cd~2, oxidative stress and other factors. The specific mechanism remains to be further studied.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R346
本文编号：2182735
[Abstract]:Quantum dots have excellent physical and chemical properties, small size effect, surface effect, quantum size effect, macroscopic quantum tunneling effect and so on. So it is widely used in many fields, such as electronics, optics, magnetism, energy and chemical industry, biomedicine, environmental protection and nanotechnology. However, with the industrialization of quantum dots, in the near future, the large-scale production and increasingly widespread application of quantum dots, it is likely to greatly increase people's exposure to and exposure to the environment of quantum dots. Therefore, it is urgent to study the biological safety and potential hazards of quantum dots. Over the years studies have shown that the hippocampus is the main site of learning and memory, the hippocampal structure is widely involved in learning and memory, and synaptic plasticity is the cellular and molecular basis of learning and memory. So. We selected the hippocampus of rats as a starting point to study the effects of chronic exposure to Streptavidin coated QDs on I / O curves, double pulse facilitation (PPF) and long duration enhanced (LTP). 1nM strep-CdSe/ZnS QD chronic exposure group animals were selected to study the effects of chronic exposure to QDs coated with Streptavidin on the input-output curve (I / O), double pulse facilitation (PPF) and long-term enhanced (LTP). There was no significant difference in fEPSP and PS I / O curves between the control group and the control group. Chronic exposure to 10 nm strep-CdSe/ZnS QD could significantly increase the amplitude of PS and fEPSP slope of I / O in rat hippocampal DG region. The basic synaptic transmission in rat hippocampal DG region was enhanced. Our previous work also confirmed that the calcium concentration of primary cultured hippocampal neurons increased significantly after the addition of high concentration quantum dots. To increase the release of certain neurotransmitters and enhance postsynaptic responses, PPF refers to the fact that when a synapse is stimulated by a short interval of double pulses, the second response is significantly stronger than the first. A short-term synaptic plasticity is described. This phenomenon is partly due to the increase in the release of neurotransmitters induced by the second stimulation, and the postsynaptic PPF in the DG region is more important than the pre-synaptic regulation. In this study, we found that chronic quantum dot exposure significantly reduced the peak value of PPF both at 0.5nM concentration and 10nM concentration. This suggests that chronic quantum dot exposure injures short-term synaptic plasticity in rat hippocampal DG region. 3 LTP is a typical activity dependent electrophysiological model of synaptic plasticity. It is recognized as the basis of cellular and molecular biology for learning and memory activities. Our experimental results show that the chronic QD exposure of 0.5 nm strep-CdSe/ZnS QD significantly reduces the inhibition of LTP by EPSP and PS LTP10nM strep-CdSe/ZnS QD QD QDs. This suggests that chronic quantum dot exposure injures synaptic plasticity in the long-term DG region of rat hippocampus. This synaptic plasticity may be related to the release of Cd~2, oxidative stress and other factors. The specific mechanism remains to be further studied.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R346
【参考文献】
相关期刊论文 前2条
1 刘舒曼,徐征,H.Wageh,徐叙tb;CdSe/CdS核/壳型纳米晶的光谱特性[J];光谱学与光谱分析;2002年06期
2 张庆彬;宋凯;孔祥贵;曾庆辉;张友林;孙雅娟;刘晓敏;;CdSe/ZnSe量子点在油水两相体系下的聚合物包覆相转移及其光谱表征[J];光谱学与光谱分析;2010年02期
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