Antidepressant-like Effect of EGb 761 in Rats with Chronic Mild Stress-induced Depressive Behaviours.

Abstract

Objective The study investigate the effects of EGb 761 on depressive behaviors in rats exposed to chronic mild stress (CMS) and the possible mechanisms of the actions. Methods Wistar rats were randomly assigned into normal group, model group and EGb 761 group. Animals in the model group and EGb 761 group were exposed to a CMS procedure lasting for 28 days. Simultaneously, rats in the EGb 761 group were daily administrated with EGb 761 by intragastric administration for 28 days. Behavioral alterations were investigated by open-field-test, sucrose preference test and forced swim test (FST). Levels of IL-1β, IL-6 and vascular endothelial growth factor (VEGF) in homogenates of hypothalamus and pituitary gland were measured by ELISA; Serum levels of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol (CORT) were detected by radio- immunoassay. Results CMS decreased locomotor activity and sucrose consumption, prolonged immobility duration in FST, elevated levels of IL-1β, IL-6, CRH, ACTH and CORT, and reduced levels of VEGF in the rats from the model group, if compared to the normal group. However, EGb 761 treatment ameliorated the CUMS-induced alterations in sucrose consumption and immobility duration without affecting locomotor activity. Moreover, EGb 761 inhibited the over-production of IL-1β, IL-6, CRH, ACTH and CORT, as well as restored the VEGF production in rats. Conclusions EGb 761 treatment had antidepressant-like effects in rats exposed to CMS.