1. Specific localization of fibroblasts at the intercalated duct in the major salivary glands of rats.
- Author
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Onozawa G, Nagasaka A, Bando Y, Sakiyama K, Yamamoto N, and Amano O
- Subjects
- Animals, Rats, Male, Submandibular Gland metabolism, Submandibular Gland cytology, Immunohistochemistry, Rats, Wistar, Parotid Gland metabolism, Parotid Gland cytology, Parotid Gland ultrastructure, Sublingual Gland metabolism, Actins metabolism, Fibroblasts metabolism, Salivary Glands metabolism, Salivary Glands cytology, Salivary Glands ultrastructure, Salivary Ducts metabolism, Salivary Ducts cytology, HSP47 Heat-Shock Proteins metabolism
- Abstract
Objectives: Immunohistochemical methods were employed to investigate the morphological heterogeneity and localization of fibroblasts associated with the function of major salivary glands in rats., Methods: Histochemical and electron microscopic observations were made in rat parotid, submandibular, and sublingual glands and pancreas. Fibroblasts were immunostained using their specific marker, 47 kDa heat shock protein (Hsp47)., Results: Hsp47-immunopositive fibroblasts within the intralobular connective tissue exhibited a notably smaller size compared with the interlobular connective tissue. They were loosely distributed throughout the connective tissue. However, fibroblasts with elongated long processes were explicitly identified at the intercalated ducts in parotid, sublingual, and submandibular glands. Fibroblastic bodies and processes were tightly approximated with the basement membrane of the duct. Electron microscopy confirmed these findings, revealing a thin layer consisting of collagen fibers was found between the fibroblasts and the basement membrane. Double staining of Hsp47 and α-smooth muscle actin (αSMA) in parotid glands indicating that Hsp47-positive fibroblasts enveloped both the duct and αSMA-positive myoepithelial cells. Additionally, They projected long and thin processes longitudinally at the straight portion or circularly at the bifurcated portion of the duct. The three-dimensional reconstruction showed a frame-like structure of fibroblasts surrounding the intercalated duct with longitudinal myoepithelial cells. However, such specific localization of fibroblasts was not detected in the exocrine pancreas lacking myoepithelium., Conclusions: Small fibroblasts with long processes connecting or overwrapping each other and thin collagen layers surround the intercalated ducts in rat major salivary glands, presumably contributing to protecting the ducts from salivary flow and myoepithelial contraction., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.)
- Published
- 2024
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