Methods: Rats were locally irradiated using a linear accelerator in the head and neck region with a single dose of 20 Gy. Phenylephrine (5 mg/kg) was injected intraperitoneally before radiation 30 min and the submandibular glands were collected on 7 day after radiation. The antiapoptotic effect of phenylephrine on the submandibular gland was examined by TUNEL assay. And the proliferative cellular nuclie antigen (PCNA) was determined by immunohistochemical assay.
Results: In comparison with the control group, the irradiation only group showed severe atrophy, enhanced cell proliferation, and increased apoptosis. The phenylephrine-pretreated group, however, showed remarkably alleviated atrophy, further increased cell proliferation, and decreased apoptosis compared to the irradiation only group.
Conclusions: The data indicate that the cytoprotective mechanisms of phenylephrine pretreatment in submandibular gland after irradiation might be related to improving cell proliferation and inhibiting cell apoptosis.