Cuadros M A, Rodríguez-Ruiz J, Calvente R, Almendros A, Marín-Teva J L, Navascués J
Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Spain.
J Comp Neurol. 1997 Dec 22;389(3):390-401.
We used the QH1 antibody to study changes in the morphological features and distribution of microglial cells throughout development in the quail cerebellum. Few microglial precursors were present in the cerebellar anlage before the ninth incubation day (E9), whereas many precursors apparently entered the cerebellum from the meninges in the basal region of the cerebellar peduncles between E9 and E16. From this point of entry into the nervous parenchyma, they spread through the cerebellar white matter, forming a 'stream' of labeled cells that could be seen until hatching (E16). The number of microglial cells in the cerebellar cortex increased during the last days of embryonic life and first posthatching week, whereas microglial density within the white matter decreased after hatching. As a consequence, the differences in microglial cell density observed in the cerebellar cortex and the white matter during embryonic life diminished after hatching, and microglia showed a nearly homogeneous pattern of distribution in adult cerebella. Ameboid and poorly ramified microglial cells were found in developing stages, whereas only mature microglia appeared in adult cerebella. Our observations suggest that microglial precursors enter the cerebellar anlage mainly by traversing the pial surface at the basal region of the peduncles, then migrate along the white matter, and finally move radially to the different cortical layers. Differentiation occurs after the microglial cells have reached their final position. In other brain regions the development of microglia follows similar stages, suggesting that these steps are general rules of microglial development in the central nervous system.
我们使用QH1抗体研究鹌鹑小脑发育过程中微胶质细胞的形态特征和分布变化。在孵化第9天（E9）之前，小脑原基中存在少量微胶质前体细胞，而在E9至E16期间，许多前体细胞显然从软膜经小脑脚基部区域进入小脑。从进入神经实质的这一点开始，它们扩散穿过小脑白质，形成一条标记细胞的“流”，这种情况一直持续到孵化（E16）。胚胎期最后几天和孵化后第一周，小脑皮质中的微胶质细胞数量增加，而孵化后白质中的微胶质细胞密度降低。因此，胚胎期在小脑皮质和白质中观察到的微胶质细胞密度差异在孵化后减小，并且在成年小脑中微胶质细胞呈现出几乎均匀的分布模式。在发育阶段发现有阿米巴样和分支较少的微胶质细胞，而在成年小脑中仅出现成熟的微胶质细胞。我们的观察结果表明，微胶质前体细胞主要通过穿过脚基部区域的软膜表面进入小脑原基，然后沿白质迁移，最后径向移动到不同的皮质层。微胶质细胞到达最终位置后发生分化。在其他脑区，微胶质细胞的发育遵循相似的阶段，这表明这些步骤是中枢神经系统中微胶质细胞发育的一般规律。
