Regeneration of acini in submandibular gland autografts

Regeneration of submandibular gland (SMG) secretory parenchyma is remarkably impaired in salivary gland diseases and under experimental conditions such as in tissue culture and after isografting. In our study acinar regeneration was found to depend on the site where the SMG tissue was implanted. Implantation of several 2-3 mm3 fragments of SMG subcutaneously in the back of the same donor adult male rat resulted in initial necrosis and mononuclear cell infiltration of the autograft. Then there was epithelial proliferation with the appearance within 28 days of lobules which contained numerous duct-like structures and only a few or no acini. In contrast, implanting SMG fragments in the anatomical bed of the donor gland resulted in the appearance of a more differentiated autograft. Although the initial tissue changes were similar to those seen in the autografts in the subcutaneous tissues of the back, the SMG autograft in the neck also contained numerous acini by 42 and 56 days after implantation. These data support the view that the implantation site influences the course of cytodifferentiation in SMG autografts.