RESUMO
INTRODUCTION: Multiple sclerosis (MS) is a chronic, demyelinating, autoimmune disease of the central nervous system causing neuroinflammation. Experimental autoimmune encephalitis (EAE) is a model of the disease. MS is classically treated with interferon beta (IFN-ß) and glatiramer acetate (GA). Melatonin (MLT) has been reported to modulate immune system responses. The aim of the present study is to analyse the effects of MLT administration in comparison with the first-line treatments for MS (IFN-ß and GA). METHODS: EAE was induced in male Sprague-Dawley rats; the animals subsequently received either IFN-ß, GA, or MLT. Cerebrospinal fluid (CSF) samples were analysed by multiplex assay to determine the levels of proinflammatory cytokines. The neurological evaluation of EAE was also recorded. RESULTS: All immunised animals developed EAE. We evaluated the first relapse-remission cycle, observing that IFN-ß and GA had better results than MLT in the clinical evaluation. Neither EAE nor any of the treatments administered modified CSF IL-1ß and IL-12p70 concentrations. However, IFN-ß and MLT did decrease CSF TNF-α concentrations. CONCLUSIONS: Further studies are needed to evaluate the molecular mechanisms involved in the behaviour of MLT in EAE, and to quantify other cytokines in different biological media in order for MLT to be considered an anti-inflammatory agent capable of regulating MS.