Tight junctions in Gerbil von Ebner's Gland: Horseradish peroxidase and freeze‐fracture studies

Abstract

The permeability of tight junctions to horseradish peroxidase (HRP) and the freeze-fracture appearance of junctional structures were investigated in the von Ebner's gland of gerbils. In the tracing study, HRP was either administered topically on the dorsal surface of tongues or injected subepithelially into the connective tissue of vallate papillae for 5-30 min. Lingual tissues containing the von Ebner's gland were sectioned and examined by light and electron microscopy. In von Ebner's glands, the reaction product for HRP was found in the intercellular and interstitial spaces, whereas HRP appeared to penetrate the tight junctions and the reaction product was localized in the lumina of serous acini. In contrast, the staining for HRP that delineated the boundary of epithelial cells was frequently observed in the superficial layers of the lingual epithelium but not the underlying tissues while applying HRP topically. Freeze-fracture replicas of acinar cells revealed that the tight junction had a depth of 0.815 ± 0.023 μm, and 4-6 parallel strands on the protoplasmic fracture face, with a branching network of joining strands with interruptions, interconnections and high linear strand density apically, and corresponding grooves on the extracellular face. Quantitative analyses showed a greater number of strands (7.217 ± 0.326) in gerbils compared to those of acinar cells (3.86 ± 0.22) in mice. These results demonstrate that the tight junctions in the gerbil von Ebner's gland is permeable, and that specific species differences in tight junction structures may be associated with the mechanism for survival in an extremely dry environment.

Microcystic adnexal carcinoma: report of rare cases

“…In our tongue MAC case, a mixture of acinus was presented around the tumor, suggesting the tumor might drive from the anterior-lingual glands. However, due to the anterior extension of Ebner's gland in the tongue body [25], the tumor might be derived from Ebner's gland as well. As the serous acinar of lingual glands and the sweat gland acinar of skin have similar histological structure and cellular construction, it is not a surprise that the MAC in the tongue has exactly the same pathologic features as the MAC derived from the sweat glands [6,15].…”