Analysis of the three dimensional organization of glia cell processes by X-ray- and high voltage electron -microscopy

通过 X 射线和高压电子显微镜分析神经胶质细胞过程的三维组织

• 批准号: 02670031
• 负责人: HAMA Kiyoshi
• 金额: $ 1.54万
• 依托单位: National Institute for Physiological Sciences (1992)Waseda University (1990-1991)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02670031/
• 关键词: glia cell; three dimensional observation; high voltage electron microscope; X-ray microscope; Golgi staining; X顕微鏡; 超高圧顕微鏡; 三次元觀察

Taking advantage of the merits of X-ray- and high voltage electron-microscopy, I examined details of the three dimensional organization of glia cell processes in various parts of the rat central nervous system.With the X-ray microscope one can observe very thick specimens of over 100 in thickness and even in water, and with the high voltage electron microscope, a high resolution observation of rather thick specimens of up to 5mum in thickness is possible. In addition , stereo observation can be done because the depth of focus of the X-ray microscope and electron microscope is very large, and in this way the information obtained from the depth of the specimens can be analyzed.Several important new findings were obtained with the aid of high voltage electron microscopy. 1) The protoplasmic astrocyte in the gray matter formed a dense three dimensional network in which terminal branches of axons and dendrites, and their synapses were embedded. The network was composed of thin leaflets or r … More ibbon-like structures of less than 50 nm in thickness. These fine branches arose directly from large branches and cell soma. They abutted on the outer surface of the capillary and fused to form a thin glial sheet in addition to that formed by rather thick astrocytic processes generally called capillary end feet. 2) The surfaces of the neurons studded with many nerve terminals are covered by astrocytic processes which formed networks covering the somata and large dendrites as seen with the light microscope. The sizes of the mesh roughly coincide with those of nerve terminals. High voltage electron microscopy revealed a layer consisting of polygonal compartments or cells which covered the soma and large dendrites. The walls of cells were consisted of a very thin astrocytic process. Each of these cells was supposed to wrap around a nerve terminal. It is interesting to note that the shapes of the processes other than those on the nerve cell somata resemble to those of the Bergmann glia cell in the cerebellum and Muller cell in the retina which are thought to originate from the radial glia cells. 3) Although global shapes of the fibrous astrocytes in the gray matter and white matter differed to each other and differed from those of the protoplasmic astrocytes, the shapes of their terminal branches were similar in principle, thin and fine leaflets or ribbonlike, and they seemed to adapt themselves to the shapes of neighboring neuronal or vascular structures.It was found that high voltage electron microscope stereoscopy of thick Golgi stained materials was the most effective and reliable method of examining the detail of the three dimensional organization of glia cell processes in the central nervous system at present.Golgi staining also gave enough contrast to glia cell processes for X-ray microscopy. Capability of observing over 100 mum thick specimen in one good focused image was a large merit of the X-ray microscope, however it's two dimensional resolution was about the same to that of the light microscope and was not high enough to resolve the details of fine terminal processes of the astrocytes. Improvement in practical resolution of the X-ray microscope is highly requested. X-ray microscopy of wet preparation will be an useful technique in glia cell morphology in the future. Less

利用X射线和高压电镜的优点，对大鼠中枢神经系统各部位胶质细胞突起的三维结构进行了详细观察，X射线显微镜可以观察到100多厚甚至在水中的标本，高压电镜可以观察到100多个胶质细胞突起的三维结构，高压电镜可以观察到100多个胶质细胞突起的三维结构。可以对厚度高达5 μ m的相当厚的样品进行高分辨率观察。此外，由于X射线显微镜和电子显微镜的焦深很大，可以进行立体观察，这样就可以分析从样品的深度获得的信息。借助于高压电子显微镜，获得了几个重要的新发现。1)灰质中的星形胶质细胞形成致密的三维网络，轴突和树突的终末分支及其突触嵌于其中。该网络由薄的小叶或小叶组成， ...更多信息 厚度小于50 nm的类铌结构。这些细枝直接由大枝和细胞索马体发出。它们邻接毛细血管的外表面并融合形成薄的胶质层，此外还有相当厚的星形胶质细胞突起（通常称为毛细血管末端足）形成的胶质层。2)光镜下可见神经元表面布满星形胶质细胞突起，形成网状结构，覆盖胞体和大树突。网格的大小大致与神经末梢的大小一致。高压电子显微镜下可见复盖于索马和大树突上的多角形隔室或细胞。细胞壁由极薄的星形胶质细胞突起构成。每一个细胞都应该缠绕在一个神经末梢上。值得注意的是，除了神经细胞胞体上的突起外，其他突起的形状类似于小脑中的Bergmann胶质细胞和视网膜中的Muller细胞，它们被认为起源于放射状胶质细胞。3)尽管灰质和白色物质中的纤维状星形胶质细胞的整体形状彼此不同，并且与原生质性星形胶质细胞的形状不同，但它们的终末分支的形状原则上相似，细而细的小叶或带状，高电压电子显微镜体视下粗高尔基体染色，材料是目前观察中枢神经系统胶质细胞突起三维结构细节最有效、最可靠的方法，高尔基体染色也能为X线显微镜提供足够的对比度。在一个良好的聚焦图像中观察超过100 μ m厚的标本的能力是X射线显微镜的一大优点，然而它的二维分辨率与光学显微镜的分辨率大致相同，并且不足以高到解析星形胶质细胞的精细末端过程的细节。提高X射线显微镜的实际分辨率是很高的要求。湿法制备的X射线显微镜技术是今后研究胶质细胞形态学的一种有用的技术。少

项目成果

K.HAMA,T.KOSAKA: "Morphology of astrocytes under the high voltage electron microscope" IN PREPARTION. (1992)

K.HAMA，T.KOSAKA：“高压电子显微镜下星形胶质细胞的形态”准备中。

K.Hama: "The three dimensional morphology of the astrocytic processes covering the surface of the neuronal soma with many terminal boutons." J.Biomedical Res.

K.Hama：“星形胶质细胞过程的三维形态覆盖了神经元胞体的表面，并有许多末端纽扣。”

K.HAMA: "Three-Dimensional morphometry of biogical fine structure using HVEM stereo images" Electron Microscopy EMSA 1991. 432 (1991)

K.HAMA：“使用 HVEM 立体图像对生物精细结构进行三维形态测量”电子显微镜 EMSA 1991. 432 (1991)

S.NAKAMURA,K.HAMA: "The transverse tubular of the hypertrophic myocardium:morphology and morphometry in spontaneous hypertensive rats (SHR)" Anatomy and Embryology. 184. 529-540 (1991)

S.NAKAMURA，K.HAMA：“肥厚心肌的横管：自发性高血压大鼠（SHR）的形态学和形态测量”解剖学和胚胎学。

K.Hama T.Kosaka: "Morphology of astrocytes under the high voltage electron mlcroscope" IN PREPARTION. (1992)

K.Hama T.Kosaka：“高压电子显微镜下星形胶质细胞的形态”准备中。