Effect of cevimeline on radiation-induced salivary gland dysfunction and AQP5 in submandibular gland in mice.

The aim of this study was to clarify the effects of the muscarinic receptor agonist, cevimeline, on saliva flow and expression of aquaporin5 (AQP5) in submandibular gland after X-ray irradiation. Using a previously established radiation-induced xerostomia model mouse, saliva flow from at 7 days before irradiation to at 28 days after irradiation was investigated in mice that were treated with cevimeline before or after irradiation. Radiation caused a significant decrease in saliva flow compared with nonirradiated salivary glands. Cevimeline post-treatment also caused a significant decrease in saliva flow. In contrast, cevimeline pre-treatment did not significantly decrease saliva flow. Expression of AQP5 fluorescent intensity and mRNA were also analyzed. Irradiation significantly decreased expression of AQP5 in submandibular gland. However, pre-treatment with cevimeline prevented this decrease in AQP5 expression. These data suggest that pretreatment with cevimeline prevents radiation-induced xerostomia and radiation-induced decrease in expression of AQP5 in submandibular gland.