AUTORADIOGRAPHIC INVESTIGATION OF GLIOGENESIS IN CORPUS-CALLOSUM OF YOUNG-RATS .2. ORIGIN OF MICROGLIAL CELLS
AUTORADIOGRAPHIC INVESTIGATION OF GLIOGENESIS IN CORPUS-CALLOSUM OF YOUNG-RATS .2. ORIGIN OF MICROGLIAL CELLS
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DOI：
10.1002/cne.901800109
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发表时间：
1978-01-01
影响因子：
2.5
通讯作者：
LEBLOND, CP
中科院分区：
文献类型：
--
作者：
IMAMOTO, K;LEBLOND, CP
新生大鼠胼胝体缺乏小胶质细胞。为了了解小胶质细胞何时以及如何随着年龄的增长而出现，对体重约为15 g的5日龄大鼠进行单次或3次短间隔注射3h -胸腺嘧啶；2 h ~ 35 d后，按不同时间间隔处死。胼胝体在侧脑室上外侧角附近取片；半薄切片放射照相并用甲苯胺蓝染色。5日龄大鼠胼胝体由松散排列的无髓鞘纤维和分散的细胞组成。在这些细胞中，小胶质细胞是罕见的；星形胶质细胞少，未成熟胶质细胞多，周细胞少见，6-7%的吞噬变形虫细胞由少量单核细胞和大量巨噬细胞组成。在给药2 h后处死的动物中，标签仅存在于未成熟细胞和变形虫细胞中。随着时间的推移，胼胝体纤维形成髓鞘，少突胶质细胞和后来的小胶质细胞出现。12日龄时，小胶质细胞大量存在；到第19天，数量翻倍，达到平稳期。许多新的小胶质细胞被标记，例如，在12日龄的动物（3h -胸腺嘧啶给药后7天）中，78.1%的小胶质细胞被标记。标记的小胶质细胞必须来自于早期获得标记的细胞的转化，即来自未成熟细胞或变形虫细胞。标记峰值的高度（未成熟细胞在第9天为59.8%，变形虫细胞在第12天为77.8%）表明后者是高度标记的小胶质细胞的前体。变形虫细胞消失，小胶质细胞出现，两者之间存在过渡成分。细胞计数表明，大约三分之一的变形虫细胞转化为小胶质细胞，而其余的则退化并死亡。在生命的前3周，胼胝体中出现的小胶质细胞是由变形虫细胞（一组巨噬细胞，从单核细胞转变为不同阶段）转化而来的。至于在第3周后或成人中偶尔出现的小胶质细胞，它们可能直接来自单核细胞。在这两种情况下，单核细胞都是最初的前体。
Microglial cells are absent from the corpus callosum of newborn rats. To find out when and how microglial cells appear with age, 3H-thymidine was given i.p. was single or 3 shortly spaced injections to 5 day old rats weighing about 15 g; and these animals were sacrificed at various time intervals from 2 h to 35 days later. Pieces of corpus callosum were taken near the superior lateral angle of the lateral ventricles; and semithin sections were radioautographed and stained with toluidine blue. The corpus callosum of 5 day old rats is composed of loosely arranged unmyelinated fibers and scattered cells. Among these cells, microglia are rare; there are a few astrocytes, many immature glial cells, rare pericytes and 6-7% of phagocytic ameboid cells consisting of a few monocytes and many macrophages. In the animals sacrificed 2 h after 3H-thymidine administration, label is present only in immature cells and ameboid cells. As time elapses and the fibers of corpus callosum become myelinated, oligodendrocytes and, later, microglial cells appear. At the age of 12 days, microglial cells are present in substantial number; and by 19 days, the number doubles to reach a plateau. Many of the new microglial cells are labeled, e.g., 78.1% in 12 day old animals (7 days after 3H-thymidine administration). The labeled microglial cells must have come from the transformation of cells that acquired label early, i.e., from the immature cells or the ameboid cells. The height of the peaks of labeling (59.8% at nine days for immature cells and 77.8% at 12 days for ameboid cells) points to the latter as precursors of the highly labeled microglial cells. The ameboid cells disappear as microglial cells appear and there are transitional elements between these 2 cell types. Cell counts suggest that about a third of the ameboid cells transform into microglial cells, while the others degenerate and die. The microglial cells which appear in the corpus callosum during the first 3 wk of life result from transformation of the ameboid cells (a group of macrophages showing various stages of transition from monocytes). As for the occasional microglial cell appearing after the 3rd wk or in the adult, they presumably come directly from monocytes. In either case, monocytes would be the initial precursors.