Histochemical Analysis of Glycoconjugates in the Lacrimal Gland of the Camel ( Camelusdromedarius )

Abstract

The mammalian lacrimal gland secretes an aqueous solution in which different chemical substances are present, including proteins and carbohydrates. The histochemical investigations on characterization of camel lacrimal secretion are limited. This study aimed to determine the histochemical properties of the dromedary camel lacrimal gland. Glandular samples of twenty healthy adult camels of both sexes were collected at Omdurman slaughterhouse, Sudan. The camel lacrimal gland was compound with tubulo-acinar mixed secretory units, having serous and mucous cells. Best’s carmine reactionwas negative, whereas a strong positive reaction to periodic acid-Schiff's (PAS) diastase resistant was observed in most of the secretory units; the reactions to alcian blue (AB pH 2.5) and aldehyde fuchsin (AF) were strong in the glandular tubules and weak or negative in the acini. Goblet cells in the epithelium of the interlobular ducts were strongly PAS, AB pH2.5 and AF positive.Both acini and tubules showed positive reactions to acid and alkaline phosphatases especially in their apical parts. These results suggest that the predominant acini secretion was serous which contained mainly neutral mucopolysaccharides, whereas the tubules secretion was mucous thatcontained sulfated and carboxylated acid mucopolysaccharides. Moreover, the different staining properties of the camel lacrimal secretion reflect various physiological functions.