Histology, histochemistry and ultrastructure of the nasopharyngeal tonsil of the buffalo ( Bubalus bubalis )

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The study examined the ultrastructural features of the palatine tonsils of the local mixed breed of adult buffaloes using scanning and transmission electron microscopy. The tissue samples collected from the palatine tonsils were fixed in 2% glutaraldehyde solution and processed for scanning and transmission electron microscopy. The scanning electron microscopy of the tonsil's surface epithelium presented folded mucosa consisting of folds divided by shallow grooves. The mucosal surface was having a squamous arrangement of cells that were delineated from the adjacent cells. These cells at higher magnification presented the microplicae, which appeared as if filled with material. A few small duct openings were irregularly placed throughout the mucosal surface. The transmission electron-microscopy elaborated structural details of the distinct strata of the surface and reticular epithelia, the cell organelles as well as the lymphocytes migration across the high endothelial venules. The vesiculo-vacuolar organelle was also observed. The study provided detailed ultramicroscopic features of the palatine tonsil, which might play a significant role in the induction of immunity against ingested antigens sampled at the mucosal surface.

Section: Introductionmentioning

confidence: 99%

Electron-Microscopic Studies on the Palatine Tonsil of the Buffalo (Bubalus bubalis)

Girgiri

Kumar

2021

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“…The passage of lymphocytes through transvascular route extends from luminal surface to exit outer basal surface of the endothelial cells [38] whereas lymphocytes attach to endothelial cells by means of short cytoplasmic projections present in interendothelial clefts and migration takes place by diapedesis through inter-endothelial trafficking [33]. The ultrastructural features of these endothelial cells especially their processes, distribution of cell organelles, presence of caveolae and vesiculovacuolar organelle (VVO's) were same as observed in the HEV's of the nasopharyngeal tonsil of buffaloes [12]. The cytoplasmic processes of the endothelial cells increased the surface area and may convert a laminar flow into a turbulent one and thus increased contacts between circulating lymphocytes and the endothelial surface [10].…”

Section: Discussionmentioning

confidence: 65%

“…A few most superficially placed dome shaped cells were designated as M-cells as reported in the sheep [18] and the pig [11]. The distinctive morphological features of M-cells had earlier been described in nasopharyngeal tonsil of the horse and buffalo by histochemical and ultrastructural techniques [7,12]. The M-cell apical surface allowed trans-epithelial transport of antigen across epithelial barrier to underlying immune cells where processing and initiation of immune responses occur [23].…”

Section: Discussionmentioning

confidence: 99%

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Light and Electron-Microscopic Studies on the Tubal Tonsil of the Buffalo (Bubalus bubalis)

Girgiri¹,

Kumar²

2020

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The tubal tonsils of 12 adult buffaloes of the local mixed breed were studied using light and electron microscopy. The tonsillar mucosa lined by pseudostratified columnar ciliated epithelium with goblet cells was modified into lymphoepithelial, due to its association with underlying lymphoid tissue. The lymphoepithelial further modified into follicle-associated epithelium (FAE) characterised by absence of the ciliated cells, goblet cells and the presence of more lymphocytes. The FAE exhibited varying modifications and presented M-cells intimately associated with lymphocytes. At places, the change of the epithelium also showed the presence of specialised M-cell like cells without any association with lymphoid tissue. The lymphoid tissue was in the form of isolated lymphocytes, diffuse aggregations and follicles. The goblet cells of the respiratory epithelium and the glandular acinar cells showed positive activity for the different carbohydrate moieties like acidic and neutral mucopolysaccharides, glycogen, mucins, weakly sulfated acidic mucosubstances, hyaluronic acid and sialomucins. Scanning electron microscopy of the mucosal surface presented a dense mat of cilia, and the FAE exhibited a heterogeneous population of microvillus and M-cells. Transmission electronmicroscopy demonstrated the different cell organelles of the various epithelia as well as the cellular profiles of the propria-submucosa, including the high endothelial venules where lymphocytes migration by both inter-endothelial and transvascular routes was also observed. The structural features of the tubal tonsil suggest that new strategies are required to explore this tonsil for targeted delivery of drugs and develop more effective vaccines by the intranasal route.

“…Six types of tonsils described in domestic mammals vary in terms of their existence and locations [6]. The detailed anatomical structure of the tonsil of the soft palate [7,8], palatine tonsil [9,10], nasopharyngeal *Address correspondence to this author at the Department of Veterinary Anatomy, College of Veterinary Sciences, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar-125 004, India; Tel: +919466402637; E-mail: pkumar@luvas.edu.in, pawanrajoria2000@rediffmail.com tonsil [11], lingual tonsil [12][13][14], and the tubal tonsil [15] has been described in the buffaloes. The paraepiglottic tonsil is absent in the horse, ox, and dog, whereas inconsistent in the goat [16].…”

Section: Introductionmentioning

confidence: 99%

Light and Electron-Microscopic Studies on the Paraepiglottic Tonsil of the Buffalo (Bubalus bubalis)

Girgiri

Kumar

2021

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The paraepiglottic tonsil present on either side of the base of the epiglottis constitutes a small portion of the mucosa-associated lymphoid tissue. The present study was conducted on the paraepiglottic tonsils of 12 adult buffaloes of the local mixed breed to explore its basic histomorphological, histochemical, and ultrastructural characteristics and to compare with other tonsils of the oral region to ascribe immunological function. The tonsil mucosa was lined by partly stratified squamous keratinised epithelium towards the outer surface and a stratified squamous non-keratinised epithelium towards the shallow crypts. The non-keratinised epithelium modified into reticular type due to infiltration of underlying lymphoid tissue was characterised by the predominance of the lymphoid cells, interrupting basement membrane and indistinct strata. The reticular epithelium at places presented a spongy appearance. The loose irregular connective tissue of propria-submucosa was mainly comprised of glandular and lymphoid tissue. The lymphoid tissue was mainly in the form of isolated lymphocytes, diffuse aggregations, and lymphoid follicles. The inter-follicular areas showed the presence of high endothelial venules. The sero-mucous type of glandular acini presented a strong reaction for glycogen, acidic mucosubstances, weakly sulfated mucosubstances, mucin, and the presence of more than 4% cysteine in their secretions. The tonsils under scanning electron microscopy presented an undulating appearance due to the presence of crest and folds. Higher magnification revealed squamous cells having various patterns and arrangements of microplicae. Small pits visualised on the mucosal surface represented openings of the glandular ducts. The cells towards the lumen of some glandular ducts appeared whorl-like where typical microplicae were absent. The transmission electron microscopy of different strata of different types of epithelia showed varying cell organelles, especially the mitochondria, endoplasmic reticulum, Golgi apparatus, and few filaments. The structural features of the tonsil were similar to those of other oral tonsils and suggested their immunological role, which might be of importance to local immunity.