基于Caspase-1/IL-18/NF-κB介导的神经炎症探讨化痰解郁方改善抑郁模型小鼠抑郁样行为的机制OA

Objective:To explore the effect and molecular mechanism of Huatan Jieyu Formula on alleviating depressive-like behaviors in mice induced by chronic unpredictable mild stress(CUMS),via regulating the Caspase-1/IL-18/NF-κB neuroinflammatory pathway in the hippocampus.Methods:A total of 60 male SPF-grade C57BL/6J mice were randomly divided into five groups,with 12 mice in each group:control group(CTR),model group(CUMS),low-dose Huatan Jieyu Formula group(HTJY-L),high-dose Huatan Jieyu Formula group(HTJY-H),and fluoxetine positive control group(FLX).Mice in the CTR group were not exposed to CUMS,while the other four groups were subjected to a 4-week CUMS procedure to establish depression models.On the next day after successful modeling,mice were intragastrically administered with corresponding drugs once daily for 4 consecutive weeks.After drug intervention,the elevated plus maze(EPM),tail suspension test(TST)and forced swimming test(FST)were performed to evaluate depressive-like behaviors of mice.Enzyme-linked immunosorbent assay(ELISA)was used to detect the protein levels of Caspase-1,IL-18 and NF-κB p65 in serum;Immunofluorescence staining to observe microglial activation in the hippocampus;Quantitative real-time polymerase chain reaction(qRT-PCR)to measure the mRNA expressions of Caspase-1 and IL-18 in hippocampal tissues;and Western blot(WB)to determine the expression of inflammatory pathway-related proteins including Caspase-1,IL-18 and NF-κB p65 in the hippocampus.Results:Compared with the CTR group,CUMS mice showed shorter open-arm residence time in EPM,longer immobility duration in TST and FST,increased Caspase-1,IL-18 and NF-κB,elevated activated microglia number in the hippocampus,upregulated Caspase-1 and IL-18 mRNA expressions(P<0.05),and increased ASC,Caspase-1,IL-18 expression and the ratios of p-AKT/AKT,p-IKKα/IKKα,p-NF-κB p65/NF-κB p65 and p-STAT3/STAT3(P<0.05).Compared with the CUMS group,mice in the HTJY-L,HTJY-H and FLX groups showed prolonged open-arm residence time in EPM and shortened immobility time in TST and FST,reduced activated microglia number in the hippocampus,and the levels of serum inflammatory factors,as well as the mRNA and protein expressions of Caspase-1 and IL-18 and other inflammation pathway-related proteins in hippocampal tissues were all downregulated(P<0.05).Compared with the HTJY-L group,the HTJY-H and FLX groups had longer open-arm residence time,shorter immobility duration and fewer activated microglia in the hippocampus.The levels of serum inflammatory factors,along with the mRNA expressions of Caspase-1,IL-18 and the expression of related inflammatory proteins in the hippocampus were further decreased(all P<0.05).Conclusion:Huatan Jieyu Formula can inhibit the activation of the Caspase-1/IL-18/NF-κB signaling pathway,alleviate central neuroinflammation,and thereby ameliorate CUMS-induced depressive-like behaviors in mice.