仔猪回肠绒毛M细胞的形态、分布及其与猪流行性腹泻病毒感染的关系

Morphological and Distribution Characteristics of Villous M Cells in the Ileum of Newborn Piglets and the Association with PEDV Infection

为了探索新生仔猪回肠绒毛上皮是否存在M细胞以及自然感染条件下猪流行性腹泻病毒(PEDV)与回肠绒毛M细胞之间的关系。采用免疫荧光、免疫组化及形态学方法研究了正常情况下仔猪回肠绒毛M细胞的分布特点和形态学特征,以及自然感染条件下PEDV与仔猪回肠绒毛M细胞之间的关系。免疫荧光结果证实正常仔猪回肠绒毛上皮存在M细胞,沿隐窝至绒毛顶端上皮方向,M细胞的数量逐渐减少。电镜下,正常仔猪的回肠绒毛M细胞具有典型的M细胞特征。自然感染PEDV的仔猪回肠绒毛M细胞病变明显,在其顶膜、细胞质、细胞核及其上皮下层均观察到成簇的PEDV颗粒,而相邻的其他上皮细胞病变不明显,且细胞内没有观察到病毒粒子。以上研究结果表明,新生仔猪回肠绒毛上皮存在M细胞,在绒毛的不同位置其分布比例存在差异。仔猪回肠绒毛M细胞可能是PEDV入侵肠道的重要通道。

The aim of this study was to identify the presence of villous M cells in the ileum of newborn piglets and determine the distribution pattern,morphological characteristics and the association with PEDV infection by immunofluorescence assay（IFA）,immunohistochemistry（IHC）and morphological methods.IFA showed a gradually decreased density of villous M cells from lower crypt epithelium to upper villous epithelium.The villous M cells showed typical morphological characteristics of M cells by electron microscope.After infected with PEDV,villous M cells in the ileum exhibited pathological changes obviously.The virus particles of PEDV were observed on theapical membrane,in the cytoplasm,around the nucleus and subepithelial of villous M cells by immunohistochemical staining of PEDV S protein,which were not observed in its adjacent epithelial cells.This study demonstrated the presence of villous M cells in the ileum of newborn piglets and determine the distribution pattern,morphological characteristics and the association with PEDV infection,suggesting the villous M cells in the ileum may be an important entry for PEDV invasion.