The identification of intestinal M cells in the sacculus rotundus and appendix of the Angora rabbit

Abstract

The present study was aimed at the immunohistochemical demonstration of M cells, found in the follicle-associated epithelium (FAE) of the sacculus rotundus (SR) and appendix of the Angora rabbit, using anti-vimentin primary antibodies, and at the determination of certain fine structural characteristics. Ten adult Angora rabbits constituted the material of the study. Immunohistochemical staining revealed that many cells composing the FAE, which covered the dome regions of the SR and appendix, reacted positively with vimentin. FAE contained two different types of vimentin-positive cells. The first type surrounded intraepithelial lymphocytes (IEL) with a basolateral invagination in the apex and periphery of the dome epithelium, whilst the second type consisted of columnar cells found in the FAE near crypts. The immunoreactivity of the cells found in the FAE covering the apex and periphery of the domes was observed particularly in the perinuclear cytoplasm and the cytoplasm surrounding the IEL. Electron microscopic examination demonstrated that the M cells found in the FAE covering the apex and periphery of the dome regions of the SR and appendix did not exhibit any microvilli on their apical surface. The FAE near crypts contained columnar cells, which resembled enterocytes. The apical membrane of these cells exhibited shorter and irregular microvilli, in contrast to neighbouring enterocytes. It was determined that M cells, found in the FAE of the SR and appendix in the Angora rabbit, displayed similarities in terms of localization and fine structure. This situation may be indicative of the two lymphoid structures with different localization having similar functional properties.

Dectin-1 gene polymorphism is associated with susceptibility to nonspecific digestive disorders and cytokine expression in rabbits1

“…In addition, the sacculus rotundus, an enlarged muscular ampulla at the distal end of the ileum, is a unique gut-associated lymphoid tissue in rabbits that plays an important role in intestinal innate immunity and adaptive immunity (Beyaz et al, 2010). In the present study, our results revealed that only the stalkless dectin-1B isoform is expressed in rabbit sacculus rotundus, and has low proinflammatory cytokines expression in nonrisk genotype even in severe intestinal inflammation stages.…”

Detection and Localization of Rabbit Hepatitis E Virus and Antigen in Systemic Tissues from Experimentally Intraperitoneally Infected Rabbits

“…In our study, we detected both viral RNA and viral antigen in different organs, especially in the three regions of the small intestine and the characteristic gut-associated lymphoid tissue (GALT)—the SR and appendix in the rabbit [24]. In our study, HEV RNA was detected in the liver, spleen, lung, lymph node, duodenum, and ileum of two inoculated rabbits at 14 dpi.…”

“…Positive signals were observed in the cytoplasm of hepatocytes and biliary epithelial cells, the epithelium of the bronchioles and alveoli, various cells in spleen and lymph node, the intestinal epithelium, and the follicle-associated epithelium (FAE) of the SR and appendix (Fig. 2) [24]. We detected no positive signals in any tissue in the negative group or in the kidneys of the inoculated group (Fig.…”

Detection of Mycobacterium avium subspecies in the gut associated lymphoid tissue of slaughtered rabbits

“…In rabbits, apart from mesenteric lymph nodes and Peyer’s patches, the GALT which accounts for 50 % of the lymphoid tissue includes two specific structures: the sacculus rotundus, and the vermiform appendix. Both tissue types present M cells [ 36 ] which actively uptake and present particular antigens and microorganisms to the immune cells of the lymphoid follicle to induce an effective immune response [ 37 ]. Map has been reported to enter the domes of the Peyer’s patches through M cells [ 38 ] so orally ingested mycobacteria should end up in these sites and/or in caecal content and therefore we chose these specimens for our analysis.…”