Investigation of age-related changes in the expression of aquaporin-1 and aquaporin-5 in the salivary glands of mice

Conclusion: The increased AQP5 expression associated with ageing in glands, which mainly secreted a serous solution, suggests a compensation for the decreased amount of saliva secretion associated with age progression. Objective: To investigate the change in aquaporin-1 (AQP1) and aquaporin-5 (AQP5) expression in the salivary glands in young and elder mice. Materials and method: Twelve female mice from the Balb/C genus (30-50g) were used. The mice were separated into two groups: Group I had 2-month-old mice and Group II had 18-month-old mice. Salivary glands (glandula parotidea, glandula sublungualis, glandula submaxillaris) were excised and examined immunohistochemically and histopathologically. AQP1 and AQP5 expression of young and elder mice was evaluated using the H-score. A p-value less than 0.05 was considered statistically significant. Results: Upon histopathological examination, the acini of glands were found to be atrophic in elder mice. The number and diameter of intercalated ducts were increased. Indeed, the amount of adipose tissue in the gland was increased. Upon immunohistochemical examination, both AQP1 and AQP5 levels in sublingual glands of elder mice were increased (p<0.01 and p<0.001, respectively). However, only AQP5 levels were increased in the parotid gland of elder mice (p<0.01).