Antidepressant-like effect of salidroside and curcumin on the immunoreactivity of rats subjected to a chronic mild stress model

Deregulated cytokines' production is found in depressed patients. Salidroside and curcumin both have been described with potential antidepressant-like activities. The present study investigated the effect of pure salidroside, curcumin and their combination on the immunoreactivity of animals, subjected to a chronic mild stress (CMS) model, followed by lipopolysaccharide (LPS)-induced inflammation. Wistar male rats were separated in the following six groups: control, CMS model, fluoxetine (2.5 mg/kg, oral), salidroside (5 mg/kg, oral), curcumin (20 mg/kg, oral) and salidroside + curcumin (5 mg/kg + 20 mg/kg, oral). Changes in glucose preference, spatial learning and exploratory behavior were recorded. The IL-6 levels in the rats' sera and of the TNF-α levels in the rats' sera and the brain tissue homogenate were evaluated. The groups exposed to stress and treated with fluoxetine, salidroside, curcumin or salidroside + curcumin showed increase in the glucose preference and locomotor activity, as well as, decrease in the escape latency and the cytokines' levels compared to the CMS model group. The chronic stress induced behavioral alternations and increased cytokines’ levels in rats which were reversed by administration of salidroside and curcumin, suggesting antidepressant-like effects comparable to that of fluoxetine and potential synergistic interaction regarding the anti-inflammatory and anti-stress effects