Histochemical localization of sialic acids and antimicrobial substances in eccrine glands of porcine snout skin

Abstract

The distribution of sialic acids and antimicrobial products (lysozyme, IgA, lactoferrin, β-defensin 2) as well as Rab3D in the eccrine glands of porcine snout skin was studied by sialoglycoconjugate histochemistry and immunohistochemistry. The secretory epithelium consisted of two types of secretory cells: dark and clear cells. The dark cells exhibited considerable amounts of sialoglycoconjugates, which included O-acetylated sialic acids, whereas sialic acids in the sequence Siaα-2-3Gal1-4GlcNAc were confined to some of the dark cells. All antimicrobial substances and Rab3D were demonstrated to be also mainly present in some of the dark cells. Additionally, in the cytological and cytochemical features, the different characteristics were observed among the dark cells. The results obtained are discussed with regard to the functional significance of the eccrine glands. The secretory products elaborated by this gland type may function as protective agents in order to preserve the skin integrity of the snout region, considering that sialic acids and antimicrobial substances are important in general defense mechanisms.

Degranulation and shrinkage of dark cells in eccrine glands and elevated serum carcinoembryonic antigen in patients with acquired idiopathic generalized anhidrosis

“…5). 20,21,25 Its function in eccrine glands is still unclear, although several functions have been suggested, such as cell adhesion, signal transduction and innate immunity. 26 The characteristic anatomical localization of dark cells, which is nearest to bacterial exposure, is suggestive of an alteration in epithelial defence mechanisms against bacteria, as well as dermcidin.…”

“…Normally, CEA is expressed on the surface and in the cytoplasm of inner cells as well as intercellular canaliculi of eccrine glands (Fig. ) . Its function in eccrine glands is still unclear, although several functions have been suggested, such as cell adhesion, signal transduction and innate immunity .…”

Comparative histology and immunohistochemistry of porcine versus human skin

“…Porcine skin contains eccrine sweat glands on the carpus and the nasolabial regions; these show a similar structure with their human counterparts [22]. However, the vast majority of porcine sweat glands are apocrine, consisting of a secretory coil lying in the deep dermis or the hypodermis, and an excretory duct.…”

Exploration of the Sialic Acid World

“…First, a light microscopic histochemical localization of sialic acids (sialoglycoconjugates) in tissue sections of eccrine glands of porcine snout skin could be carried out by employing a method that includes a selective periodate oxidation-phenylhydrazine blockade and a thiocarbohydrazide-silver protein sequence, followed by a physical development procedure. 395,396 Second, for the in situ imaging by confocal laser microscopy and flow cytometric quantification of sialylated glycoproteins on living human gastric normal and cancer cells, the cell lines were treated by mild periodate oxidation (1 mM, 4°C, up to 20 min), and the aldehyde functions generated on the glycoproteins were ligated with the fluorescence tag, fluorescein-5-thiosemicarbazide. 397 Note that the chosen periodate oxidation conditions only introduce aldehyde groups into the sialic acid glycerol side chains of the glycoproteins on the living cell surface.…”