Age- and sex-dependent effect of exogenous melatonin on expression pattern of melatonin receptor (MT1 and MT2) proteins in spleen of mice

Spleen is an important lymphoid organ which exerts immune activities throughout the life in mammals. In this study, we investigated the age- and sex-dependent effect of exogenous melatonin on expression pattern of MT1 and MT2 melatonin receptor proteins in spleen of laboratory Swiss albino mice in three different age-groups – 2, 4, and 8 months. The melatonin receptor expression patterns were studied by immunohistochemical localization and Western blot analysis. Immunohistochemical study showed reactivity of MT1 and MT2 melatonin receptors in spleen of both male and female mice. Exogenous melatonin significantly showed age- and sex-dependent expression pattern of MT1 receptor protein, while MT2 receptors showed only age-dependent differential expression patterns in both male and female mice. Therefore, this study may suggest that exogenous melatonin is modulating MT1 and MT2 receptor protein expression pattern in age- and sex-dependent manner in spleen of mice.