Regeneration of submandibular gland autografts in sympathectomized rats

This morphologic study compares the regenerative response in submandibular gland (SMG) autografts placed in the tongues of previously sympathectomized rats to autografts placed in tongues of sham-sympathectomized rats. We hypothesized that sympathectomy would alter the process of cellular proliferation and inhibit cytodifferentiation in regenerating SMG autografts. Either 1 week, or 8 to 11 weeks following the SMG autografting procedure, the rats were sacrificed and their tongues were removed and sectioned in a cryostat. Frozen tissue sections containing the SMG autografts were either reacted for cholinesterase activity, treated with a glyoxylic acid mixture to induce histofluorescence, or stained for histologic examination. In addition, 3H-thymidine labeled and unlabeled cells were counted in autoradiographs of 1-week autografts, and these counts were used to calculate labeling indices. The 1-week SMG autografts from both the sympathectomized and the sham-sympathectomized rats were similar in histologic appearance, and neither group of autografts contained cholinesterase-positive or monoaminergic nerve fibers. The 8- to 11-week autografts from sympathectomized and sham-sympathectomized rats contained cholinesterase-positive fibers, but monoaminergic fibers were present in the autografts only from the sham-operated rats. Acinar cells were observed in one-third of the 8- to 11-week autografts of both the sympathectomized and sham-sympathectomized rats. This finding suggests that sympathectomy did not prelude cytodifferentiation in the autografts. The autoradiographic data revealed no statistically significant difference between the mean labeling indices of the 1-week autografts from the sympathectomized and sham-sympathectomized rats, which suggests that sympathectomy also did not alter the level of cellular proliferation in the autografts.