Genital organ-associated lymphoid tissues arranged in a ring in the mucosa of cow vaginal vestibules. (July 2022)

• Record Type: Journal Article
• Authors: Chuluunbaatar, Tsolmon; Ichii, Osamu; Masum, Md. Abdul; Namba, Takashi; Islam, Md. Rashedul; Otani, Yuki; Elewa, Yaser Hosny Ali; Kon, Yasuhiro
• Is Part Of: Research in veterinary science. Volume 145(2022)
• Page Start: 147
• Page End: 158
• Publication Date: 2022-07
• Subjects: Cow -- Genital organ associated lymphoid tissue -- Lymphoid ring -- Lymphatic follicle -- Diffuse lymphoid tissue; Veterinary medicine -- Periodicals; Veterinary Medicine -- Periodicals; Médecine vétérinaire -- Périodiques; Médecine vétérinaire -- Recherche -- Périodiques; Diergeneeskunde; 636.089
• DOI: 10.1016/j.rvsc.2022.02.011
• Languages: English
• ISSNs: 0034-5288

Abstract

Abstract: Female reproductive tracts are equipped with local and mucosal immune systems; however, structural information remains unclear for farm animals. In this study, the mucosa-associated lymphoid tissue-like structures in cow reproductive tracts were described. Vaginal vestibule (VV) and external parts of the genital organ, including the clitoris and vulva, were morphologically analyzed. Whole-mount specimens revealed several hematoxylin-positive spots arranged in a ring in the mucosa. Histologically, these spots were aggregated immune cells and defined as genital organ-associated lymphoid tissues (GOALTs). GOALTs were composed of lymphatic follicles (LFs) or diffuse lymphoid tissues (DLTs) at different depths of lamina propria. LFs frequently contained germinal centers. Scattered lymphocytes occupied the border area between follicles and epithelium, whereas DLTs had indefinite shapes. GOALTs contained immune cells and high endothelial venules. B cells were dominant both in LFs and DLTs. Abundant collagenous fibers were stretched across VV lamina propria, whereas reticular fibers were primarily observed in the DLT rather than LF. The epithelium covering of GOALTs was partially or fully disrupted by the invasion of immune cells toward the VV lumen. These findings suggest GOALTs function as a "genital lymphoid ring" as in Waldeyer's pharyngeal ring and act as immunological gate systems in cow reproductive tracts. Highlights: Whole-mount staining revealed lymphoid tissues on the mucosa of vaginal vestibule. Lymphoid tissues showed two types: lymphatic nodule or diffuse lymphoid tissue. Disrupted epithelium allowed passage for immune cells into the intraluminal space.