Effects of long-term etanercept treatment on anxiety- and depression-like neurobehaviors in rats

Growing evidence indicates that there is a correlation between depression and inflammation. Administration of anti-tumor necrosis factor (TNF) agents for treatment of chronic inflammatory diseases, such as psoriasis, was associated with decreased depressive symptoms and increased quality of life in some clinical studies. The aim of the present study was to investigate the effects of chronic etanercept, a TNE-alpha inhibitor, on anxiety- and depression-like neurobehaviors in rats. Male rats were treated for 8 weeks with either saline or etanercept (0.8 mg/kg/week, subcutaneously). The anxiety levels of rats were evaluated using the elevated plus maze, a classical rodent model of anxiety and depression was measured using the force swimming test, a behavioral despair task. The anxiety-like neurobehaviors of the animals were found significantly decreased after the etanercept treatment. Etanercept significantly decreased immobility time in rat model of despair test, seemed to have an antidepressive effect in rats. Compared to saline treatment, long-term etanercept treatment had no effect on the total number and pattern of locomotor activities. Findings of the study supported the hypothesis that TNE-alpha has a role in the modulation of emotional processes and its inhibition may represent a novel strategy for the treatment of affective disorders. (C) 2013 Elsevier Inc. All rights reserved.