Distribution of aquaporin-5, transforming growth factor-β1 and laminin during regeneration of atrophic rat submandibular glands after duct ligation

摘要

The aim of this study was to determine the localization of aquaporin-5 (AQP5), transforming growth factor-βsub1/sub (TGF-βsub1/sub) and laminin during regeneration of the rat submandibular gland. After duct ligation for 7 days, the regenerating glands were collected on days 0, 1, 3, 7, and 14 after ligation release to study the process of regeneration. Immunohistochemical staining revealed apical expression of AQP5 in many acinar cells, strong expression in intercalated ducts (ICDs) of the normal submandibular gland at Day 14, and strong expression in duct-like structures (DLSs) during regeneration from Day 0 to 7. However, a few AQP5-negative acinar cells were detected during regeneration. At Day 0, immunopositivity for TGF-βsub1 /subwas detected in connective tissue. At Days 3 and 7 during regeneration, TGF-βsub1/sub immunostaining was observed in DLSs, which were surrounded by α-smooth muscle actin-positive thickened myoepithelial cells. Laminin staining was strong in the thickened basement membrane of DLSs at Day 3 during regeneration, but weak around acinar cells at Day 14. These findings suggest that TGF-βsub1/sub is involved in the environment around DLSs, myoepithelial cells and laminin, that DLSs have the same functional properties as ICDs, and that AQP5-negative acinar cells may be mucous cells.