Regeneration of the intralobular duct and acinus in rat submandibular glands after YAG laser irradiation.

The present study was performed to understand the regeneration of the intralobular duct and acinus of partially injured salivary glands. Sections of rat submandibular glands irradiated with YAG laser were investigated histologically, and the proliferative activity of regenerating tissue was also investigated immunohistochemically with anti 5-bromo-2'-deoxyuridine (BrdU) monoclonal antibody. After YAG laser irradiation, duct-like structures continuous to the remaining ducts were regenerated at the periphery of the injured lobule. At the distal end of the duct-like structures, squamous cells were shown to form epithelial clusters. Additionally, immature acinar cells appeared budding off from the duct-like structures. During regeneration, BrdU-positive cells were observed in these duct-like structures, epithelial clusters, and immature acini. This study showed that duct-like structures, epithelial clusters and immature acini appear during the regeneration process of partially injured lobules, and that each structure proliferated in order to contribute to the rapid regeneration of the salivary gland.