Exploring The Potential Antidepressant Mechanisms Of Puerarin Based On The Model Of Chronic Restraint Stress

Objective: By establishing a chronic restraint stress(CRS)mouse depression model,we observed the antidepressant effects of puerarin in CRS mice and elucidated the potential link between puerarin and the "gut-liver-brain axis",providing new theoretical support for the investigation of the antidepressant mechanism of puerarin.Methods: Firstly,we established a 4-week depression model in CRS mice,and based on the results of previous studies,we chose the antidepressant effect of puerarin at a dose of 100 mg/kg and fluoxetine as a positive control to investigate the intervention effect of puerarin on depression and the potential mechanism.The Sucrose preference test(SPT),Tail suspension test(TST),Open field test(OFT),Novelty suspended feeding test(NSFT)and Forced swim test(FST)were used to observe behavioral changes in mice to assess its antidepressant effects.The gut microbial composition was analyzed by 16 S r RNA gene sequencing.Histopathological changes in the colon and liver were also observed by HE staining.The levels of Lipopolysaccharide(LPS)in the colon,serum,liver and prefrontal cortex(PFC)and 5-hydroxytryptamine(5-HT)in the PFC were measured by enzyme-linked immunosorbent assay(ELISA).And AST and ALP in the serum were measured by microplate.Finally,the contents of Brain-derived neurotrophic factor(BDNF),TLR4 protein,MYD88 protein,p-IκB-α protein and p-p65 protein in mouse PFC were measured by Western Blot(WB).Results: The results showed that puerarin was effective in alleviating CRS-induced depression-like behaviors measured in SPT,TST,FST and NSFT in mice.Compared with the CRS model group,puerarin increased the rate of sucrose preference rate in SPT,shortened the cumulative immobility time in TST and FST,and the feeding delay period in NSFT in depressed mice.In addition,puerarin administration modulated CRS-induced dysregulation of the intestinal microbiota in mice,elevating the abundance of Lactobacillaceae,Lactobacillus,and decreasing the abundance of Ruminococcaceae,Ruminococcus,Desulfovibrionaceae and Prevotella.In addition,puerarin also reduced LPS,AST and ALP levels in depressed mice,improved colon and liver tissue damage in depressed mice,and inhibited TLR4/MYD88/NF-κB signaling pathway-mediated neuroinflammatory damage,upregulated 5-HT and BDNF levels in the PFC of mice,thereby reversing CRS-induced depression-like behavior.Conclusion: Puerarin improves CRS stress-induced depression in mice by modulating the "gut-liver-brain axis" and its related molecules.For example,by modulating the CRS-induced intestinal flora disorder and intestinal permeability changes,the systemic LPS levels and the relative levels of AST and ALP were reduced,and the activation of TLR4/MYD88/NF-κB signaling pathway by LPS was inhibited,thereby reducing neuroinflammatory damage and ultimately improving the depressive symptoms in CRS mice.