OMgp及其受体NgR在中枢神经系统发育中和损伤后表达及其意义的实验研究

发布时间：2018-09-13 14:33

【摘要】： 受多种因素的影响,中枢神经系统(Central nervous system,CNS)损伤后难于再生,如损伤后髓鞘抑制蛋白的再生抑制作用,神经营养因子的缺乏,胶质瘢痕的形成,以及随之而来的抑制再生的主要蛋白聚糖的上调等。然而从损伤发生到胶质瘢痕形成的这段时间内,再生在很大程度上还是受髓鞘抑制蛋白的影响,有研究表明将小鼠在脊髓损伤前用髓鞘进行免疫后有一定程度的再生。目前鉴定出的髓鞘抑制蛋白有三种,分别是髓鞘相关糖蛋白(myelin-associated glycoprotein,MAG)、Nogo和最近才发现的少突胶质细胞髓鞘糖蛋白(oligodendrocyte-myelin glycoprotein,OMgp)。这三种抑制蛋白都分布于髓鞘膜表面,与轴突毗邻,处于介导轴突-胶质细胞相互反应的最佳位置。OMgp的抑制作用由于在三者中发现最晚,因而对它的研究相对较少。啮齿类动物出生后CNS发育中OMgp mRNA以及蛋白的表达已有研究报道,但胚胎发育过程中OMgp的表达情况目前尚缺乏研究,成年动物CNS中OMgp的表达情况可能与胚胎期有所不同,将对OMgp表达的研究从出生后往前延伸至胚胎期对于全面了解OMgp的功能将有很大的帮助。OMgp也表达于神经元,其功能尚不得而知,对CNS损伤后OMgp在神经元和胶质细胞表达变化的研究与比较将为深入探讨其功能打下基础,但目前还未见报道。另外,OMgp与Nogo、MAG虽然没有明显的序列相似性,但是都通过一个共同的受体——NgR来发挥其抑制作用,NgR由于在再生抑制信号传导中的枢纽作用而倍受关注。近年来人们发现这种髓鞘抑制蛋白的受体不仅在神经元有表达,在少突胶质细胞等非神经元细胞类型也有表达,但少突胶质细胞所表达的NgR是否与CNS的损伤及再生有联系尚无实验证据。本文运用RT-PCR、免疫组织化学等方法,从mRNA和蛋白两个不同水平,将配体OMgp与受体NgR结合起来同时研究,并将大鼠从胚胎期经成年期直至老年期的整个过程连贯起来全面观察,研究比较OMgp及其受体NgR在CNS发育中的表达,旨在了解OMgp、NgR与CNS发育的关系;同时通过建立大鼠脊髓全横断模型,研究了大鼠脊髓横断损伤后OMgp、NgR在神经元和少突胶质细胞的表达,探讨CNS损伤后OMgp、NgR在神经元和少突胶质细胞表达变化的规律及意义。
[Abstract]:Under the influence of many factors, it is difficult to regenerate after (Central nervous system,CNS injury, such as the inhibitory effect of myelin inhibitor protein, the deficiency of neurotrophic factor, the formation of glial scar. And the subsequent inhibition of regeneration of the main proteoglycan upregulation and so on. However, during the period from injury to glial scar formation, regeneration is still affected by myelin inhibitor protein to a large extent. Some studies have shown that mice can regenerate after immunization with myelin sheath before spinal cord injury. At present, three myelin inhibitory proteins have been identified: myelin associated glycoprotein (myelin-associated glycoprotein,MAG) and recently discovered oligodendrocyte myelin glycoprotein (oligodendrocyte-myelin glycoprotein,OMgp). These three suppressor proteins are located on the surface of myelin sheath and adjacent to axons. The inhibitory effect of OMgp on axon-glial interaction is at the best position of mediating axon-glial interaction. The expression of OMgp mRNA and protein in postnatal CNS development of rodents has been reported, but the expression of OMgp in embryonic development has not been studied. The expression of OMgp in CNS of adult animals may be different from that in embryonic stage. Extending the study of the expression of OMgp from postnatal to embryonic stage will be of great help in understanding fully the function of OMgp. OMgp is also expressed in neurons, the function of which is not known. The study and comparison of the expression of OMgp in neurons and glial cells after CNS injury will lay a foundation for further study of its function, but it has not been reported yet. In addition, although there is no obvious sequence similarity between OMgp and Nogo,MAG, both of them exert their inhibitory effects through a common receptor, NgR. NgR has attracted much attention because of its pivotal role in regenerative inhibitory signal transduction. In recent years, it has been found that the myelin inhibitory protein receptor is expressed not only in neurons, but also in non-neuronal cell types such as oligodendrocytes. However, whether the NgR expressed by oligodendrocytes is associated with CNS damage and regeneration has not been demonstrated. In this paper, RT-PCR, immunohistochemical method was used to combine ligand OMgp with receptor NgR from two different levels of mRNA and protein, and to observe the whole process of rat from embryonic stage through adult to old age. To study the expression of OMgp and its receptor NgR in the development of CNS, to understand the relationship between OMgp,NgR and CNS development, and to study the expression of OMgp,NgR in neurons and oligodendrocytes after spinal cord transection in rats by establishing a rat spinal cord transection model. To investigate the expression and significance of OMgp,NgR in neurons and oligodendrocytes after CNS injury.
【学位授予单位】：第三军医大学
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：R363

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