McMenamin Paul G, Djano Jenny, Wealthall Rosamund, Griffin Brendan J
School of Anatomy and Human Biology and. Centre for Microscopy and Microanalysis, The University of Western Australia, Crawley (Perth) 6009, Australia.
Invest Ophthalmol Vis Sci. 2002 Jul;43(7):2076-82.
The tunica vasculosa lentis (TVL) is a transient vascular network surrounding the developing lens that regresses prenatally in humans and postnatally in rodents. Macrophage-like cells, sometimes referred to as hyalocytes, have been postulated to play a role in the regression of this vascular system; however, the precise identity of these cells is still unclear. The aim of the present investigation was to provide phenotypic data on these cells in combination with their three-dimensional distribution on the lens surface during the period when regression of the TVL is taking place. To this end the authors have used a novel combination of silver-enhanced immunogold labeling and environmental scanning electron microscopy (ESEM).
The eyes of Wistar rats at various pre- and postnatal ages (E20, postnatal days [D]0, 2, 5, 7, and 10) were studied by either conventional scanning electron microscopy (SEM) or ESEM. The latter was used to study specimens that had been incubated with various antileukocyte monoclonal antibodies (ED1, ED2, Ox6, Ox42), followed by immunolabeling with gold-conjugated secondary antibody visualized by silver enhancement.
Conventional SEM of the developing lens revealed a pattern of radial and interconnecting vessels in the TVL similar to previous studies. In addition, large numbers of cells with the morphologic characteristics of macrophages were noted on the lens surface closely associated with the vessels. The gradual attenuation and regression of vessels was noted over the course of the time period investigated. Immunolabeled specimens examined by ESEM revealed that most of the macrophage-like cells were indeed ED1(+) and ED2(+) (both pan-macrophage markers) and MHC class II(-) (Ox6) and CD11b/18(-) (Ox42): a phenotype characteristic of macrophages. This phenotype altered little between E20 and D10.
The cells surrounding the developing lens that are postulated to play a role in regression of the TVL have the morphologic and immunophenotypic characteristics of resident tissue macrophages similar to those previously identified in the adult rodent uveal tract and the vitreous (hyalocytes). This phenotype differs from that of dendritic cells and microglia; however, it is postulated that lens-associated macrophages are ideally located to act as a source of retinal microglia after completion of their role in TVL regression.
晶状体血管膜（TVL）是围绕发育中晶状体的一个短暂血管网络，在人类产前退化，在啮齿动物产后退化。巨噬细胞样细胞，有时被称为透明细胞，被推测在这个血管系统的退化中起作用；然而，这些细胞的确切身份仍不清楚。本研究的目的是在TVL退化期间，结合这些细胞在晶状体表面的三维分布，提供关于这些细胞的表型数据。为此，作者使用了银增强免疫金标记和环境扫描电子显微镜（ESEM）的新颖组合。
通过常规扫描电子显微镜（SEM）或ESEM研究不同产前和产后年龄（胚胎第20天、出生后第0、2、5、7和10天）的Wistar大鼠的眼睛。后者用于研究与各种抗白细胞单克隆抗体（ED1、ED2、Ox6、Ox42）孵育后的标本，随后用银增强可视化的金偶联二抗进行免疫标记。
发育中晶状体的常规SEM显示，TVL中存在与先前研究相似的放射状和相互连接的血管模式。此外，在晶状体表面发现大量具有巨噬细胞形态特征的细胞，这些细胞与血管紧密相关。在所研究的时间段内，观察到血管逐渐变细和退化。通过ESEM检查的免疫标记标本显示，大多数巨噬细胞样细胞确实是ED1(+)和ED2(+)（两者都是泛巨噬细胞标记物），且MHC II类(-)（Ox6）和CD11b/18(-)（Ox42）：这是巨噬细胞的表型特征。这种表型在胚胎第20天和出生后第10天之间变化不大。
围绕发育中晶状体的细胞被推测在TVL退化中起作用，它们具有常驻组织巨噬细胞的形态和免疫表型特征，类似于先前在成年啮齿动物葡萄膜和玻璃体（透明细胞）中鉴定的细胞。这种表型不同于树突状细胞和小胶质细胞；然而，据推测，晶状体相关巨噬细胞在完成其在TVL退化中的作用后，处于理想位置可作为视网膜小胶质细胞的来源。
