Extract From Morinda Officinalis Improves Depressive Symptoms In Mice By Regulating Gut Microbiota And Affecting KP Pathway

Objective: Objective to investigate whether the extract of Morinda officinalis.affects tryptophan kynurenine(KP)pathway by regulating gut microbiota.and tryptophan2,3-dioxygenase(TDO),so as to improve LPS(Lipopolysaccharides)induced depression in mice.Methods: Thirty Weight 20-25 g male ICR mice were randomly divided into three groups: control group,model group,Morinda officinalis treatment group and positive drug group.The control group was given intraperitoneal injection of normal saline from the 11 th day,and the other groups were given intraperitoneal injection of LPS for 5consecutive days.The concentrations were 0.052,0.104,0.208,0.415 and 0.83 mg/kg,respectively.Meanwhile,the treatment group were given Morinda officinalis iridoid extract(11.25 mg / kg)and,and the control group and model group were given the same volume of drinking water by gavage.After 15 days of forced swimming,sucrose preference test was performed.After 15 days of forced swimming,sucrose preference test was performed.The levels of Trp,Kyn in serum,KYNA and QA in brain were detected by ELISA.The expression of TDO in liver was detected by q PCR.The feces of mice were collected to detect the gut microbiota(diversity and richness of microorganisms in mice).Results: the swimming,tail suspension,field and sucrose preference experiments of mice all verified the success of the model group,and the depression symptoms of mice in Morinda officinalis treatment group were significantly improved.Compared with the control group,the ratio of Kyn in serum,Kyn / Trp and QA / KYNA and quinolinic acid(QA)in brain of LPS model group increased,while the ratio of Trp in serum,KYNA in brain decreased,with statistical significance(*P<0.05).q PCR was used to detect the expression of tryptophan 2,3-dioxygenase(TDO)m RNA in the liver of mice.The expression in the model group increased,while that in the treatment group decreased compared with the model group(*P<0.05).In the report of gut microbiota,through the analysis of Wayne diagram,sparse curve(alpha diversity),distance matrix,PCo A analysis and thermogram,it is clear that Morinda officinalis administration group can improve depression by regulating the relative abundance of Corynebacterium and Bifidobacterium.Conclusion: The extract of Morinda officinalis has therapeutic effect on depressive mice by regulating intestinal flora and tryptophan kynurenine(KP)metabolic pathway.