The dura mater contains abundant macrophages whose functions remain largely elusive. Recent studies have demonstrated the origin, as well as the gene expression pattern, of dural macrophages (dMΦs). However, their histological features have not been explored yet. In this study, we performed immunohistochemistry and electron microscopy to elucidate their precise morphology, localization, and postnatal development in mice. We found that the morphology, as well as the localization, of dMΦs changed during postnatal development. In neonatal mice, dMΦ exhibited an amoeboid morphology. During postnatal development, their cell bodies elongated longitudinally and became aligned along dural blood vessels. In adulthood, nearly half of the dMΦs aligned along blood vessel networks. However, most of these cells were not directly attached to vessels; pericytes and fibroblasts interposed between dMΦs and vessels. This morphological information may provide further indications for the functional significance of dMΦs.

中文翻译：

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硬脑膜巨噬细胞的形态、定位和出生后发育

硬脑膜含有丰富的巨噬细胞，其功能在很大程度上仍然难以捉摸。最近的研究已经证明了硬脑膜巨噬细胞 (dMΦs) 的起源和基因表达模式。然而，它们的组织学特征尚未被探索。在这项研究中，我们进行了免疫组织化学和电子显微镜检查，以阐明它们在小鼠中的精确形态、定位和出生后发育。我们发现 dMΦs 的形态和定位在出生后发育过程中发生了变化。在新生小鼠中，dMΦ 表现出变形虫形态。在出生后的发育过程中，它们的细胞体纵向拉长并沿着硬脑膜血管排列。在成年期，近一半的 dMΦ 沿血管网络排列。然而，大多数这些细胞并不直接附着在血管上。周细胞和成纤维细胞介于 dMΦ 和血管之间。这种形态信息可以为 dMΦ 的功能意义提供进一步的指示。