Objective:To investigate the relationship between the depressive behaviors of rats induced by chronically unpredictable stress(CUS) and the change of glycogen synthase kinase-3beta(GSK-3β) expression and oxidative stress. Methods:Totally 30 Sprague Dawley(SD)rats were randomly divided into control group and model group. CUS with solitary condition was taken to establish rat depression model. The open-field test(OFT)and forced swim test(FST)were used to assess the anxiety- and despair-like depression behaviors of rats;superoxide dismutase(SOD)

catalase(CAT)

and malondialdehyde(MDA) levels were used to evaluate oxidative stress and anti-oxidative stress level;the real time PCR and Western blot were used to determine and assess the change of GSK-3β m RNA and protein expression in rat’s brains. Results:It showed that the movements in OFT decreased(P=0.000)and the immobility time in FST increased significantly(P=0.000);CAT and SOD activities decreased significantly(P=0.000)with obviously increased MDA level(P=0.014)and GSK-3β m RNA and protein expression(P=0.000;P=0.028)in model group compared with those in control group. Conclusion:The mechanism of the anxiety- and despair-like depression behaviors of rats induced by CUS maybe involved in upregulating GSK-3β expression and oxidative stress.