Effect And Mechanism Of Chlorogenic Acid On Cognitive Dysfunction In Mice Due To Lipopolysaccharide-Induced Neuroinflammation

Objective:To investigate the effects of chlorogenic acid on cognitive dysfunction due to neuroinflammation and to investigate the mechanisms by which it acts,providing new evidence for the treatment of neuroinflammation and cognitive dysfunction.Methods:Study on the effect of chlorogenic acid on lipopolysaccharide-induced neuroinflammation in mice:LPS(750 μg/kg/d)was injected intraperitoneally into C57BL/6 mice for 7 consecutive days to construct a neuroinflammation model,and chlorogenic acid(40 mg/kg/d)was given for 4 days pretreatment followed by 7 consecutive days treatment.The cognitive dysfunction of the mice was observed by neurobehavioral scoring,open field experiment and water maze experiment,the expression level of inflammatory factors in the brain tissue of the mice was detected by ELISA,the neuronal damage in the brain was observed by HE staining and immunohistochemistry,and the activation of microglia and M1/M2 polarization in the hippocampal region of the brain tissue was observed by immunofluorescence staining.Chlorogenic acid inhibited lipopolysaccharide-induced M1-type polarization and migration of BV-2cells and promoted M2-type polarization of BV-2 cells: CCK-8 results showed that 50,100 and 200 μM chlorogenic acid had no significant effect on normal survival of BV-2.Western blot and flow cytometry results showed that chlorogenic acid could inhibit lipopolysaccharide-induced polarization of BV-2 cells toward M1-type and promote their polarization toward M2-type polarization and promote their polarization to M2 type.The results of Western blot for the migration-associated protein MMP9 also showed that chlorogenic acid reduced the enhanced migratory ability of lipopolysaccharide-induced BV-2 cells.Chlorogenic acid inhibits cognitive dysfunction due to neuroinflammation by inhibiting the activation of Akt1,TNF,MMP9,PTGS2,MAPK1,MAPK14,RELA in the TNF signaling pathway: Venn diagram results showed that there were 117 targets for chlorogenic acid,neuroinflammation,and cognitive dysfunction.The Cytoscape results,arranged according to the degree value from largest to smallest,showed that the top 20 proteins were Akt1,TNF,CASP3,EGFR,MMP9,PTGS2,MTOR,PPARG,SIRT1,MAPK1,NOS3,APP,ICAM1,CXCR4,MAPK14,VCAM1,CXCL12 KEGG enrichment analysis showed that among these core targets,7 targets,namely Akt1,TNF,MMP9,PTGS2,MAPK1,MAPK14 and RELA,were mainly enriched in the TNF signaling pathway,i.e.chlorogenic acid exerted its effects on improving neuroinflammation-induced cognitive dysfunction by regulating the above targets.Western blot results showed that the protein phosphorylation levels of Akt1,MAPK1,MAPK14 and RELA increased in the LPS group,and the protein expression levels of TNF and PTGS2 increased in the LPS+CGA group compared to the LPS group.The protein phosphorylation levels of Akt1,MAPK1,MAPK14,RELA and TNF and PTGS2 were decreased in the LPS+CGA group.Conclusions:In conclusion,this study used network pharmacological analysis,molecular docking techniques,and in vivo and ex vivo experiments to elucidate the role played by chlorogenic acid in a model of lipopolysaccharide-induced neuroinflammation and to explore the potential mechanisms by which chlorogenic acid acts.The results obtained indicate that chlorogenic acid significantly inhibits M1-type polarization and promotes M2-type polarization in microglia,thereby ameliorating lipopolysaccharide-induced neuroinflammation.The mechanism involved may be achieved by inhibiting the activation of NF-κB and MAPK signaling in the TNF signaling pathway,which in turn inhibits the expression of inflammatory mediators.