Behavioral aspects of experimental autoimmune encephalomyelitis

Acute inflammation is known to induce a depressive-like sickness behavior syndrome in humans and in experimental animals. In the present study, we sought to determine whether a chronic neuroautoimmune inflammation is also associated with a similar behavioral syndrome. Experimental autoimmune encephalomyelitis (EAE) was induced in SJL/J female mice by adoptive transfer of lymph node cells, and sickness behavior symptoms, including anorexia, loss of body weight, reduced social exploration, and decreased preference for sucrose solution were measured. We report that these components of sickness behavior were induced during the acute phase of the disease, and recovered in later phases. Moreover, the onset and recovery of the behavioral symptoms preceded the onset and recovery of the neurological signs, respectively. Since EAE is considered a model for multiple sclerosis (MS), it is suggested that EAF-induced behavioral changes may serve as a model for the depressive symptomatology that characterizes most MS patients.