Anti-Inflammatory properties of a testosterone metabolite in an experimental model of multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease affecting the CNS and characterized by neuroinflammation. Clinical observations revealed different incidence between males and females, suggesting a possible influence of sex steroids. These molecules, produced by peripheral steroidogenic glands, can exert their actions into the CNS, directly, or after metabolic conversion, and, for this reason, they are also called neuroactive steroids. Observations on experimental autoimmune encephalomyelitis (EAE) rodents, the most used animal model for MS, also suggest an involvement for neuroactive steroids in the pathology. In particular, castration worsen, while testosterone or its metabolite dihydrotestosterone (DHT) improve the pathological course of the disease. Based on these evidences, male Dark Agouti rats were induced with EAE in order to develop a relapsing-remitting pathology, similar to the most common human form of MS. EAE animals were treated with DHT or vehicle (sesame oil) and monitored through the experiment. After 45 days post induction, we evaluated inflammatory parameters in spinal cord tissues. The pathological course was improved in EAE rats treated with DHT compared to vehicle. Moreover, neuroinflammatory parameters such as microglial and astrocytes markers as well as cytokine expression and thiobarbituric acid-reactive substances, that were increased in the EAE-vehicle group, are significantly reduced after treatment with DHT. In conclusion, DHT treatment ameliorates not only the pathological course of the disease but also neuroinflammatory parameters in spinal cord tissues. These observations may suggest DHT as potential therapeutic option for male MS patients.