title: Distribution of collagen fibers in the aggregated lymphoid follicles of swine terminal ileum.
abstract: The arrangement of the collagen bundles was studied in the Peyer's patches of swine terminal ileum, by means of light microscopy (using silver-impregnation technique and picrosirius F3BA staining) and scanning electron microscopy (after NaOH-maceration). The lymphoid tissue forms a large and continuous patch along the antimesenteric border. The follicles are disposed mainly in the tela submucosa and sometimes they reached in the tunica mucosa surface (follicle/dome structures). Some follicles are located in the lamina propria of the tunica mucosa. Light microscopy showed black and brown-stained fibers, and yellow and red, and green-stained fibers, respectively by silver impregnation technique and picrosirius red staining, in the tela submucosa. In this tela, by scanning electron microscopy, the collagen fibers appeared as thick bundles forming a network of parallel layers. This network was denser in the interfollicular than in the follicular area, and formed a capsule surrounding the lymphoid follicles. Our results pointed out that a clear correspondence exists between the findings of currently used light microscopy techniques and the scanning electron microscopy after alkali-water maceration method. The arrangement of the collagen fibers in the antimesenteric border of the tela submucosa suggested a functional compartmentalization within the aggregated lymphoid follicles. This could facilitate the antigen-to-cell and cell-to-cell interaction during the immune response and thus create a suitable microenvironment for an active cell metabolism. The tunica mucosa showed a porous structure and its frequent gaps were likely the sites through which lymphocytes and other cells could freely migrate thus participating in the immunological activities of these structures.
authors.affiliation: Department of Morphophysiological Science, University of Maringá, Parana, Brazil. immprado@uem.br
authors.forename: Isaura M M
authors.initials: IM
authors.lastname: Prado
authors.forename: Liberato J A
authors.initials: LJ
authors.lastname: Di Dio
authors.forename: Marcílio Hubner
authors.initials: MH
authors.lastname: Miranda-Neto
authors.forename: Sonia Lucy
authors.initials: SL
authors.lastname: Molinari
authors.forename: Tiziana
authors.initials: T
authors.lastname: Stallone
authors.forename: Guido
authors.initials: G
authors.lastname: Macchiarelli
authors.forename: Pietro M
authors.initials: PM
authors.lastname: Motta
mesh_terms: D000818:Animals; D003094:Collagen / Q000032:analysis* / Q000648:ultrastructure*; D004396:Coloring Agents; D007082:Ileum / Q000166:cytology* / Q000648:ultrastructure; D007413:Intestinal Mucosa / Q000166:cytology* / Q000648:ultrastructure; D008297:Male; D008855:Microscopy, Electron, Scanning; D010581:Peyer's Patches / Q000166:cytology* / Q000648:ultrastructure; D013552:Swine
chemical_list: D004396:Coloring Agents; D003094:Collagen