Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Tochigi, 329-0498, Japan.
Cell Tissue Res. 2022 Sep;389(3):427-441. doi: 10.1007/s00441-022-03660-7. Epub 2022 Jul 2.
Our previous studies using immunohistochemistry and serial block-face scanning electron microscopy (SBF-SEM) clarified that fibroblast-like cells (FBLCs) in the rat ileal mucosa are classifiable into several subtypes, but their characteristics throughout the large intestine remain unknown. In this study, we investigated the region-specific characteristics of FBLCs in the rat large intestine using histological analysis including SBF-SEM. Immunohistochemistry revealed that CD34CD31 FBLCs were localized in the lamina propria beneath the crypt bases throughout the large intestine and were more abundant in the descending colon than in the other regions. In addition, platelet-derived growth factor receptor α (PDGFRα) FBLCs were ubiquitously present just below the epithelium throughout the large intestine, and those at the crypt base were slightly more abundant in the descending colon than in the other regions. SBF-SEM analysis revealed that there were two types of FBLCs around the crypt base in both the cecum and the descending colon: sub-epithelial FBLCs localizing just beneath the epithelium in the manner of PDGFRα FBLCs, and lamina propria FBLCs localizing farther away from the epithelium than sub-epithelial FBLCs in the manner of CD34CD31 FBLCs. The lamina propria FBLCs were closely apposed to various immune cells in the lamina propria, and their endoplasmic reticulum in the descending colon exhibited various dilatation levels, unlike that in the cecum. These findings indicate that FBLCs, especially around the crypt base, differed in each region of the large intestine with respect to localization, abundance, and ultrastructure, which could lead to the region-specific microenvironment around the crypt base.
我们之前的研究使用免疫组织化学和连续块面扫描电子显微镜（SBF-SEM）阐明，大鼠回肠黏膜中的成纤维细胞样细胞（FBLCs）可分为几个亚型，但它们在整个大肠中的特征尚不清楚。在这项研究中，我们使用包括 SBF-SEM 在内的组织学分析研究了大鼠大肠中 FBLCs 的区域特异性特征。免疫组织化学显示，CD34CD31 FBLCs 定位于整个大肠的隐窝基底下方的固有层中，在降结肠中比在其他区域更为丰富。此外，血小板衍生生长因子受体α（PDGFRα）FBLCs 普遍存在于整个大肠的上皮下方，在隐窝基底处，降结肠比其他区域略多。SBF-SEM 分析显示，在盲肠和降结肠的隐窝基底周围存在两种类型的 FBLCs：定位于上皮下方的上皮下 FBLCs，以 PDGFRα FBLCs 的方式定位；以及远离上皮的固有层 FBLCs，以 CD34CD31 FBLCs 的方式定位。固有层 FBLCs 与固有层中的各种免疫细胞紧密相邻，其在降结肠中的内质网表现出各种扩张水平，与盲肠不同。这些发现表明，FBLCs，特别是在隐窝基底周围，在大肠的每个区域在定位、丰度和超微结构方面都存在差异，这可能导致隐窝基底周围的区域特异性微环境。
