Ultrastructural Changes of Epithelium Covering Peyer's Patch by Simple Obstruction of Gerbil Ileum

Lee, Gi Jeong; Han, Eui Hyeog; Kim, Hyoung Tae

Abstract

The light and electron microscopic studies were carried out to find the morphological changes of epithelial cells covering Peyer's patch after simple observation of gerbil (Mongolian gerbil) ileum. Animals were classified as the control, 6 hour-ligation and 18 hour-ligation groups. Terminal ileum was ligated with white silk around Peyer's patch without the vascular injury. In control group, epithelia of the gerbil ileum was consisted of villous epithelium and follicle-associated epithelium (FAE) covering Peyer's patch. FAE represented typical dome structure, and was composed of the cuboid absorptive cells mainly and M cells. M cells were distributed at the periphery rather than central portion of dome-like FAE that are distinguishable from absorptive cells, owing to their typically short and thick microvilli on its free surface. In the light mictoscopy on 6 hour-ligation group, cells with vacuoles were appeared in FAE, and some lymphocytes in lymphoid follicle were condensed and then densely stained. There are many lymphocytes in FAE, infiltrated through the interrupted basement membrane. In the electron microscopic findings of 6-hour-ligated group, absorptive cells appeared to have many vesicle and vacuoles in various size, some lipid droplets and membranous structure contained inclusion bodies. Microvilli of M cell appeared to be destroyed at the central portion on its free surface. In the light microscopy of 18 hour-ligation group, FAE destructed partially and lymphoid follicle was hypertrophied and atrophied simultaneously. In the electron microscopic findings of 18 hour-ligation group, absorptive cells appeared to have the irregular and densely stained nucleus, and have many lipid droplets other than structures observed in 6 hour-ligation group. M cell appeared to have various-sized vacuoles, and have the bleb-like and irregular membrane-limited structures that protrude into the lumen and have less the cytoplasmic cell organs. These results suggested that the simple ligation of ileum gives rise to the inflammatory response on FAE of 6 hourligated group and then lead to the various response; degeneration, necrosis and atrophy of cells in FAE, and the hypertrophy and atrophy of lymphocytes in lymphoid follicle. M cell might have no special function and have the degenerative change with the adjacent absorptive cells during simple obstruction.