Evaluation of protective effect of propolis on parotid salivary glands in gamma-irradiated rats.

OBJECTIVE AND BACKGROUND One of the most significant side effects of radiotherapy for head and neck cancers is xerostomia as a result of salivary gland damage. Considering pharmaco- logical effects of propolis, we evaluated its protective effect on salivary glands subjected to radiotherapy of head and neck cancer patients. MATERIALS AND METHODS Twenty-one male albino rats (8-11 W, 190 ± 5 gm) were divided into three groups of seven animals. Scintigraphy was performed in all the groups. Then groups 1 (S) and 2 (SR) received normal saline injections and group 3 (PR) received propolis injection over 3 days. After that groups 2 and 3 were exposed to gamma radiation and all the rats underwent scintigraphic assessment on third day and 70th day after irradiation. The lips and tongues of rats in groups 2 and 3 were examined for mucositis daily in first 10 days. At the end, the parotid glands of all rats were examined histologically. RESULTS Scintigraphy results of third and 70th day after irradiation showed statistically significant differences between PR and SR as well as SR and S. However, there was no significant difference between the PR and S groups. Histopathologic assessment demonstrated significant difference between SR, PR and S. CONCLUSION These results suggest that propolis has protective effects on salivary gland function in animal models whilst it did not prevent radiation-induced histologic changes in tissues. Further investigations are needed to elucidate mechanisms of propolis actions. Clinical significance: Regarding to the results of this study, propolis may be useful in reduction xerostomia due to radiation to salivary glands and may be helpful for head and neck cancer patients.