Sodium selenite is a potent radioprotector of the salivary glands of the rat: acute effects on the morphology and parenchymal function during fractioned irradiation.

In vitro studies show that sodium selenite is a potential radioprotector in normal cultural cells, but not in tumor cells. The aim of this study was to evaluate the cytoprotective potency of sodium selenite during a conventional fractioned irradiation of the salivary glands of rats. The head and neck area of male WAG/RijH rats was irradiated with (60)Co-gamma rays (60 Gy/30 fractions/6 weeks). Sodium selenite (15 microg/kg body weight) was applied through a venous port 30 min before irradiation. Rats of a control group were treated in the same manner with an equal volume of physiologic sodium chloride. In the course of treatment, the salivary glands were resected at different stages and examined histopathologically. The evaluation of gland function was performed prior to and after radiotherapy by sialoscintigraphy. The irradiation caused dose-dependent damage in the salivary glands. Intra- and intercellular edema (16 Gy), vacuolization (30 Gy), degranulation (46 Gy) and necrosis of the acinar cells (60 Gy) occurred. Sodium selenite delayed the development of the described damage; additionally, the number of necrotic acinar cells after the application of 60 Gy was reduced (control, 75% vs. sodium selenite, 30%). The sialoscintigaphical results confirmed these results: the loss in gland function in the control group was 74 vs. 44% (P < 0.05) in the sodium selenite group. Based on the morphological and sialoscintigraphical findings, a cytoprotective effect on the acute toxicity of the salivary glands of rats could be detected during irradiation with synchronous application of sodium selenite.