Cytochemistry of sialoglycoconjugates, lysozyme, and [beta]-defensin in eccrine glands of porcine snout skin as studied by electron microscopy

In most mammals except for humanoid primates, eccrine glands are confined to the skin of a series of specific body regions. Sialic acids and antimicrobial substances exhibit various functional properties and serve as a component of nonspecific defense against micro-organisms, respectively. In this study, the distribution of these moieties was studied by electron microscopic histochemical methods. The eccrine glandular acini consisted of two types of dark cells as well as clear cells. The secretory granules and Golgi apparatus of both types of dark cells contained sialic acid residues linked to [alpha]2-6Gal/GalNAc. On the other hand, sialoglycoconjugates with Si[alpha]2-3Gal[beta]1-4GlcNAc sequence were confined to those of the Type II dark cells. In addition, lysozyme and [beta]-defensin were mainly detected in the secretory granules of the Type II dark cells. These secretory products may create a defensive barrier against microbial invasion and play an essential role in preservation of the integrity of porcine snout skin as a sensory organ. Microsc. Res. Tech. 2013. © 2012 Wiley Periodicals, Inc. [PUBLICATION ABSTRACT]