Veterinary Research International | July-September, 2015 | Vol 3 | Issue 3 | Pages 55-59 © 2015 Jakraya Publications (P) Ltd VETERINARY RESEARCH INTERNATIONAL Journal homepage: www.jakraya.com/journal/vri ORIGINAL ARTICLE Histology, Histochemistry and Scanning Electron Microscopy of Lingual Tonsil of Young Pigs Ranjit, Pawan Kumar* and Gurdial Singh Department of Veterinary Anatomy, College of Veterinary Sciences, LUVAS, Hisar-125 004 (Haryana), India. *Corresponding Author: Pawan Kumar Email: pkumar@luvas.edu.in Received: 05/09/2015 Revised: 25/09/2015 Accepted: 27/09/2015 Abstract The present study was conducted on lingual tonsil of 10 young male pigs of 8-10 months age of local mixed breed for light and scanning electron microscopic studies. The lingual tonsil was lined by stratified squamous keratinized to non-keratinized epithelium having different strata. This epithelium modified into reticular epithelium especially toward the crypts was associated with lymphoid tissue. Propria submucosa had loose irregular connective tissue, glandular tissue, fatty tissue and lymphoid aggregations mainly in the form of follicles. These follicles were separated by interfollicular areas having lymphocytes, plasma cells, macrophages, fine blood capillaries and high endothelial venules. The mucous type of glandular acini presented strong reaction for glycogen, acidic and neutral mucopolysaccharides. The scanning electron microscopy revealed that the surface of the lingual tonsil was having different types of papillae with broader base and pointed tips except a few having blunt tips. The higher magnification revealed flat epithelial cells and different arrangements of microplicae. Key words: Reticular epithelium, Lingual tonsil, Pigs, High Endothelial Venules. 1. Introduction The lingual tonsil formed by the collection of tonsillar or crypto-lymphatic units at the base of the tongue (Nair and Rossinsky, 1984) has been termed follicular glands (Balgdrusen) with structural similarity to tonsil and other lymphoid tissue (Kollilker, 1855). The stratified squamous keratinized or non-keratinised epithelium modifies into reticular epithelium towards crypts which are constantly exposed to alimentary and airborne antigens and acts as first line of defense by neutralizing or containing infectious agents and by initiating and maintaining immune responses (Perry, 1994). It also functions as an additional lymphoid compartment by contributing to the production of committed immunocytes and to the protection of the mucosal surface (Brandtzaeg and Halstensen, 1992). The tonsils of pigs have been studied either with preliminary report (Casteleyn et al., 2011) or except the lingual tonsil (Liu et al., 2012). The present study describes in detail the histological architecture, histochemistry and scanning electron microscopy of lingual tonsil in pigs. 2. Material and Methods 2.1 Light Microscopy The present study was conducted on 10 young male pigs of 8-10 months age, of local mixed breed. The heads were procured from local slaughter house immediately after decapitation. The tissues of lingual tonsil for histomorphological and histochemical studies were used from 5 heads and fixed in 10 per cent neutral buffered formalin solution for 48 hours. The fixed tissues were processed for routine paraffin technique for light microscopy. The paraffin sections of 5-6 μ were cut and stained with routine Harris’ hematoxylin and eosin stain, Gomori’s method for reticulum, Weigert’s method for elastic fibres (Luna, 1968), Crossman’s trichrome stain for collagen fibres (Crossman, 1937), McManus’ method for glycogen (PAS), Alcian blue method for muco-substances (pH 2.5), PAS-Alcian blue method for acidic and neutral mucosubstances (pH 2.5), Meyer’s mucicarmine method for mucin, colloidal iron method for acid mucopolysaccharides (Luna, 1968). 2.2 Scanning Electron Microscopy