Abstract:To explore the effect and mechanism of nuts (walnut and sweet almonds) on prevention of depression, chronic unpredictable mild stress (CMS) model was used to mimic depression. Immobility time in forced swimming test (FST), sucrose consumption in sucrose preference test, corticosterone (CORT) levels in plasma, expression of brain-derived neurotrophic factor (BDNF), protein kinase A (PKA) and protein kinase C (PKC) in hippocampus were measured respectively. Our results showed that the performance of behavior in model group was significant decrease compared with control group (P<0.05). Pretreatment of nuts markedly improved the performance in FST and sucrose preference test. Nut group has a significant difference compared with model group (P<0.05). These results suggest that pretreatment of nuts ameliorate the depression. In the test of CORT measured, although CORT level in plasma of model group was significant enhancement compared with control group (P<0.05), nuts group didn't decrease the CORT level in plasma compared with model group (P>0.05). It suggested that prevention of depression of nuts might not be related to the reduction of CORT. In western blot test, hippocampal expression of BDNF, PKA and PKC in model group was significant decrease compared with control group (P<0.05). On the contrary, pretreatment of nuts reversed the reduction of the expression of BDNF, PKA and PKC compared with model group (P<0.05), suggesting that antidepressant effect of nuts is related to activate PKA, PKC and increase the expression of BDNF signaling pathway. Therefore, these results suggest that pretreatment of nuts alleviate the depression, providing theories and experimental foundation for prevention of depression through eating nuts.