Histology, ultrastructure, and carbohydrate cytochemistry of surface and glandular epithelium of human nasal mucosa.

Abstract

AbstractExamined histologically, the surface epithelium lining the nasal cavity was observed to consist of ciliated, mucous, and basal cells. Coiled serous tubules were found to populate stroma beneath the epithelium and to open directly onto the surface. In deeper glandular lobules, serous demilunes and tubules drained into branched mucous tubules that connected with interlobular ducts.Light‐microscopic cytochemical properties of gobletlike mucous cells of surface epithelium indicated that, if they secrete a single glycoprotein species, this secretory product contains hexoses with vic glycols, subterminal galactose, terminal sialic acid, and sulfate esters on internal residues. With the same assumption, mucous cells in the glands can be viewed as producing a slightly different glycoprotein which also contains periodate‐reactive hexose, a terminal galactose‐sialic acid dimer and, in some cells but not others, sulfate esters on internal residues. Serous cells in the glands produced secretion with relatively light staining, demonstrative of lower levels of periodate‐reactive sulfated glycoprotein lacking in terminal galactose‐sialic acid dimers. Serous cells also disclosed immunoreactivity for lysozyme.At the electron‐microscopic level all mucous cells of the surface epithelium possessed granules with a loose meshwork that stained for glycoprotein containing periodate‐reactive hexose. The meshwork in most surface mucous cells stained also for content of sulfated glycosubstance. Three types of mucous cells were distinguished in the surface epithelium on the basis of the size of their secretory granules, content of a spherical glycoprotein‐free core in the granules, and intensity of staining of the matrix meshwork for sulfate esters. Endocrinelike cells with periodate‐reactive, sulfated glycoprotein in their granules occurred in a deep and in a superficial location in the surface epithelium.Cells in glandular serous tubules generally disclosed a uniform population of monozonal granules or of bizonal granules with a periphery containing periodatereactive, sulfated glycoprotein. The morphology of these secretory granules and their staining for sulfated glycosubstance varied markedly between serous cells. Cellular variability in granule characteristics was more marked from one tubule to another than from one to another cell in the same tubule profile. Occasional serous cells appeared to contain two granule types showing typical secretory granules and a population of small elongated granules reminiscent of those in the endocrinoid cells.Mucous cells in glandular mucous tubules differed somewhat from surface mucous cells in the morphology and cytochemistry of their granules. The granules varied between glandular mucous cells, in content of a carbohydrate‐free core and staining for sulfomucin. Granule heterogeneity was evident in some glandular mucous cells stained for sulfomucin. Some tubule profiles, possibly located at serous‐mucous transition points, exhibited atypical “mucous” cells with trizonal granules and unusual serouslike cells.