The Effect of Melatonin on Behavioral, Molecular, and Histopathological Changes in Cuprizone Model of Demyelination

Multiple sclerosis (MS) is an autoimmune, demyelinating disease of the central nervous system. The protective effects of melatonin (MLT) on various neurodegenerative diseases, including MS, have been suggested. In the present study, we examined the effect of MLT on demyelination, apoptosis, inflammation, and behavioral dysfunctions in the cuprizone toxic model of demyelination. C57BL/6J mice were fed a chaw containing 0.2 % cuprizone for 5 weeks and received two doses of MLT (50 and 100 mg/kg) intraperitoneally for the last 7 days of cuprizone diet. Administration of MLT improved motor behavior deficits induced by cuprizone diet. MLT dose-dependently decreased the mean number of apoptotic cells via decreasing caspase-3 and Bax as well as increasing Bcl-2 levels. In addition, MLT significantly enhanced nuclear factor-kappa B activation and decreased heme oxygenase-1 level. However, MLT had no effect on interleukin-6 and myelin protein production. Our data revealed that MLT improved neurological deficits and enhanced cell survival but was not able to initiate myelin production in the cuprizone model of demyelination. These findings may be important for the design of potential MLT therapy in demyelinating disorders, such as MS.