Rungger-Brändle E, Messerli J M, Niemeyer G, Eppenberger H M
University Eye Clinic, Geneva, Switzerland.
Eur J Neurosci. 1993 Aug 1;5(8):1093-106. doi: 10.1111/j.1460-9568.1993.tb00963.x.
The distribution of astrocytes in the vascularized retina of pigs, rats and cats was investigated by confocal microscopy and computer-assisted image processing. In whole mounts, immunocytochemical identification was done by staining astrocytes for glial fibrillary acidic protein (GFAP), and blood vessels for alpha-smooth muscle actin or collagen IV. Double-staining was followed through consecutive optical sections and made it possible to precisely align the two markers in the inner retina. The resulting computer-assisted image reconstructions revealed asymmetric ensheathment of blood vessels by GFAP-positive fibres. The ultrastructural basis for this asymmetry, as studied by electron microscopy, was found to be different in pigs and cats. In the pig, astrocytes firmly ensheathed the vessel circumference, but glial filaments were much more abundant on the vitreal and lateral than on the scleral side. By contrast, in the cat astrocytes were generally confined to regions occupied by axonal bundles and constituted only part of the vascular glia limitans, else formed by Müller cells. Moreover, our observations unambiguously showed that individual astrocytes maintained simultaneous contact with axons and blood vessels and lined the vitreous body. The physical links provided by astrocytes suggest that they are able to function as central communicating elements between ganglion cells, the vasculature and the vitreous body.
通过共聚焦显微镜和计算机辅助图像处理技术，研究了猪、大鼠和猫的血管化视网膜中星形胶质细胞的分布情况。在整装标本中，通过对星形胶质细胞进行胶质纤维酸性蛋白（GFAP）染色以及对血管进行α-平滑肌肌动蛋白或IV型胶原染色来进行免疫细胞化学鉴定。通过连续光学切片进行双重染色，使得能够在内层视网膜中精确对齐这两种标记物。由此产生的计算机辅助图像重建显示，GFAP阳性纤维对血管的包裹不对称。通过电子显微镜研究发现，这种不对称的超微结构基础在猪和猫中有所不同。在猪中，星形胶质细胞牢固地包裹血管周围，但胶质丝在玻璃体侧和外侧比在巩膜侧丰富得多。相比之下，在猫中，星形胶质细胞通常局限于轴突束占据的区域，仅构成血管神经胶质界膜的一部分，其余部分由米勒细胞形成。此外，我们的观察明确表明，单个星形胶质细胞同时与轴突和血管接触，并排列在玻璃体表面。星形胶质细胞提供的物理连接表明它们能够作为神经节细胞、脉管系统和玻璃体之间的中央通讯元件发挥作用。
