Distribution Of Actin-filament And Α6β1/α3-integrin During Rat Submandibular Gland Regeneration

Objectives: Many experiments have been performed, using a duct ligation model, to analyze the atrophy and regeneration. But the little attention has been paid to the extracellular matrix.The aim of this study was to determine the localization of α6β1- and α3-integrin and their involvement in actin cytoskeleton during regeneration of submandibular gland.

Methods: The alteration of actin filaments was examinated by phalloidin, which specifically binds to F-actin to elucidate the role of cytoskeleton during regeneration of rat submandibular gland. In addition, α6β1- and α3-integrins were investigated immunohistochemically to analyze the relationship between the changes in the cytoskeleton and integrins. After 7 day's obstruction the regenerating glands were collected at days 0, 1, 3, 7, 11 and 14 after duct release to study regeneration.

Results: F-actin reactions were strongly observed at the apical regions of duct-like structures at days 3-7. As acinar cells differentiate, F-actin reactions were observed at the cortical site of mature cells. Strong labeling of α3-integrin was detected at the apical and lateral regions of duct-like structures during regeneration. The α6β1- integrin was expressed strongly in the maturing acinar cells during the early stage of regeneration. The double immunostains of α6β1- and α3-integrins revealed that at day3, α3-integrins were observed at immaturing acinar cells, and α6β1-integrins at more mesial site than α3-integrins.

Conclusions: These findings suggest that the localization of α3-integrin and the alteration of actin cytoskeleton affect cells polarization and differentiation, and α6β1-integrin is involved in the differentiation of the acinar cells during regeneration of rat submandibular gland.