Resveratrol reverses the effects of chronic unpredictable mild stress on behavior, serum corticosterone levels and BDNF expression in rats.

Depression is one of the most common neuropsychiatric disorders and has been associated with the neuroendocrine system and alterations in specific brain proteins. Resveratrol is a natural polyphenol enriched in polygonum cuspidatum and has diverse biological activities, including potent antidepressant-like effects. The present study attempts to explore the mechanisms underlying the antidepressant-like action of resveratrol by measuring serum corticosterone levels and the content of brain derived neurotrophic factor (BDNF) in the hippocampus and amygdala of rats exposed to the chronic unpredictable mild stress (CUMS). Male Wistar rats were subjected to the CUMS protocol for a period of 5 weeks to induce depressive-like behavior. Resveratrol treatment (20, 40 and 80mg/kg/i.p. 5 weeks) significantly reversed the CUMS-induced behavioral abnormalities (reduced sucrose preference, increased immobility time and decreased locomotor activity) and the elevated serum corticosterone levels observed in stressed rats. Additionally, 5-weeks of CUMS exposure significantly decreased BDNF levels in the hippocampus and amygdala, and was accompanied by decreased phosphorylation of extracellular signal-regulated kinase (pERK) and cAMP response element-binding protein (pCREB), while resveratrol treatment normalized these levels. All of these effects of resveratrol were essentially identical to that observed with the established antidepressant, desipramine. In conclusion, our study shows that resveratrol exerted antidepressant-like effects in CUMS rats, mediated in part by normalizing serum corticosterone levels while up-regulating pERK, pCREB and BDNF levels in the hippocampus and amygdala.