选择性杀死小胶质细胞对星形胶质细胞和神经元的影响

发布时间：2018-10-24 22:02

【摘要】：小胶质细胞是中枢神经系统中一种重要的细胞组分,在啮齿类动物中,其数量占胶质细胞总数的5%-20%。作为中枢神经系统中特异性的免疫效应细胞,小胶质细胞在维持中枢神经系统平衡中起到关键性的作用。在病理条件下,小胶质细胞会快速活化,并在损伤区周围聚集。在本实验中,结合CX3CR1CreER/+:R26iDTO/+转基因小鼠和光化学栓塞模型,探究了在特异性杀死小胶质细胞后,新生小胶质细胞的来源,并分析了在中风损伤中小胶质细胞和星形胶质细胞的活化反应,并进一步研究了中风后神经元的死亡和存活。通过将携带Rosa26-stop-DTR (R26iDTR)等位基因的小鼠和在小胶质细胞中表达他莫昔芬诱导Cre重组酶的CX3CR1CreER小鼠相杂交,获得CX3CR1CreER/+:R26iDTR/+转基因小鼠。通过他莫昔芬和白喉毒素(DT)的处理,使得CX3CR1CreER/+:R26iDTO/+转基因小鼠表达白喉毒素受体(DTR),从而使小胶质细胞对白喉毒素的敏感性加强,建立特异性杀死小胶质细胞的体系。实验结果表明,在进行他莫昔芬和白喉毒素的处理后,转基因鼠中Iba-1阳性细胞的数量减少了90.7%；此后,小胶质细胞的数量会逐渐增加,并在数周内恢复至正常水平。本文的研究结果表明,新生小胶质细胞来源于本地小胶质细胞的增殖；选择性杀死小胶质细胞可导致海马区域星形胶质细胞的急性活化,但尼氏染色结果表明神经元变化不明显,而中风后,不仅可引起星形胶质细胞的活化,而且会导致退行性神经元数量的增加。因而,小胶质细胞的缺失对正常大脑神经结构的完整性影响不大,但在中风条件下对胶质细胞的激活和神经元的退行性变化产生了一些影响。本论文的研究为脑中风的治疗提供了一些参考依据。
[Abstract]:Microglia is an important cellular component in the central nervous system. In rodents, the number of microglia accounts for 5- 20% of the total number of glial cells. As specific immune effector cells in the central nervous system, microglia play a key role in maintaining the central nervous system balance. Under pathological conditions, microglia are rapidly activated and congregate around the injured area. In this study, CX3CR1CreER/: R26iDTO/ transgenic mice and photochemical embolization model were used to investigate the origin of newborn microglia after specific killing of microglia. The activation of microglia and astrocytes in apoplectic injury was analyzed, and the death and survival of neurons after stroke were further studied. CX3CR1CreER/: R26iDTR/ transgenic mice were obtained by hybridization between mice carrying Rosa26-stop-DTR (R26iDTR) allele and CX3CR1CreER mice expressing tamoxifen induced Cre recombinant enzyme in microglia. Through the treatment of tamoxifen and diphtheria toxin (DT), CX3CR1CreER/: R26iDTO/ transgenic mice expressed diphtheria toxin receptor (DTR), which enhanced the sensitivity of microglia to diphtheria toxin and established a specific killing system for microglia. The results showed that after treatment with tamoxifen and diphtheria toxin, the number of Iba-1 positive cells in transgenic mice decreased 90.7 and the number of microglia increased gradually and returned to normal level within a few weeks. The results of this study indicate that the newborn microglia are derived from the proliferation of native microglia, and selective killing of microglia can lead to acute activation of astrocytes in the hippocampal region. However, the results of Nissl staining showed that the changes of neurons were not obvious. After stroke, not only the activation of astrocytes was induced, but also the number of degenerative neurons was increased. Therefore, the absence of microglia has little effect on the integrity of normal cerebral nerve structure, but has some effect on the activation of glial cells and the degeneration of neurons under stroke. This paper provides some references for the treatment of cerebral apoplexy.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R743.3

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