Eosinophils are abundantly present in intestinal mucosa. However, the morphological characteristics of their cellular population are still largely unknown. In this study, we examine their characteristics in the rat ileal mucosa using histological and ultrastructural methods. The results indicated that ileal eosinophils could be distinguished into two main groups based on their nuclear shapes and distribution: eosinophils with spheric or reniform nuclei mainly localized in the villous region and eosinophils with annular or bacilliform nuclei as the major population around crypts. Immunohistochemical analysis revealed that all eosinophils in the lamina propria (LP) were immunopositive for CD11b, whereas eosinophils in LP of the intestinal villus but not those in LP around the crypt, were immunopositive for CD11c. Three-dimensional ultrastructural analysis using serial block-face scanning electron microscopy showed that the eosinophils with spheric or reniform nuclei were abundant in the upper portions of the intestinal villus, whereas those with annular nuclei were abundant in the lower portions of the intestinal villus and around crypts. The eosinophils with spheric or reniform nuclei possessed broader cellular bodies with greater abundance of surface projections compared with those with annular nuclei. Eosinophils in the upper portions of intestinal villus frequently extended their cellular bodies into the intraepithelial space. The number of total and eosinophil-specific granules was positively correlated with the minor axis of the nuclear holes in the annular nuclei. These data suggest that ileal eosinophils exhibit not homogenous but rather diverse characteristics, possible due to the mixture of eosinophils at different maturation and/or activation stages.

中文翻译：

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大鼠回肠嗜酸性粒细胞的形态和表型多样性

嗜酸性粒细胞大量存在于肠粘膜中。然而，它们细胞群的形态特征在很大程度上仍是未知的。在这项研究中，我们使用组织学和超微结构方法检查了它们在大鼠回肠粘膜中的特征。结果表明，回肠嗜酸性粒细胞根据其核形状和分布可分为两大类：球形或肾形核的嗜酸性粒细胞主要位于绒毛区，而嗜酸性粒细胞以环状或杆状核作为隐窝周围的主要群体。免疫组织化学分析显示固有层 (LP) 中的所有嗜酸性粒细胞对 CD11b 呈免疫阳性，而肠绒毛的 LP 中的嗜酸性粒细胞，而不是隐窝周围的 LP 中的嗜酸性粒细胞，对 CD11c 呈免疫阳性。连续块面扫描电镜三维超微结构分析显示，肠绒毛上部富含球形或肾形核的嗜酸性粒细胞，而肠绒毛下部及周围富含环状核的嗜酸性粒细胞。地穴。与环状核的嗜酸性粒细胞相比，具有球形或肾形核的嗜酸性粒细胞具有更宽的细胞体和更丰富的表面突起。肠绒毛上部的嗜酸性粒细胞经常将它们的细胞体延伸到上皮内空间。总的和嗜酸性粒细胞特异性颗粒的数量与环状核中核孔的短轴呈正相关。