Effect And Study On The Intervention Mechanism Of Peanut Skin Procyanidins On Ulcerative Colitis

Ulcerative colitis(UC)is a nonspecific inflammatory bowel disease characterized by persistent superficial inflammation of the mucosa and submucosa confined to the colon and rectum.Its etiology and pathogenesis are very complex,easy to recurrent,seriously affect the quality of life of patients.How to prevent or intervene the occurrence and development of UC has been widely concerned by researchers.Dietary polyphenols have become a research hotspot in recent years because of their anti-inflammatory,antiviral and intestinal ecology improvement activities.Peanut skin is the main by-product of peanut processing,which is rich in dietary polyphenols such as A-type procyanidins.To study the ameliorative effect of Peanut skin procyanidins(PSP)rich in A-type procyanidins on UC and its potential mechanism,the present study established UC model in Balb/C mice induced by DSS,and evaluated the ameliorative effect of PSP on inflammation and oxidative stress.In vitro and in vivo models were used to explore the potential mechanism of PSP in protecting the inflammatory intestinal barrier,and analyzed the effects of PSP on intestinal microbes and metabolic pathways in UC mice.The main contents and experimental results of this study are as follows:1.Preliminary study on the mechanism of PSP improving UC symptom representation.DSS induced UC mice was established.It was found that PSP intervention could significantly relieve the symptoms of DSS induced body weight loss and colon length shortening,and effectively reduce DAI score.At the same time,the content of ROS,MDA,NO,i NOS in UC mice was significantly decreased(p<0.01),and the oxidative stress disorder in UC mice was alleviated.The levels of anti-inflammatory cytokines IL-10 were increased(p<0.01),and the contents of pro-inflammatory cytokines TNF-α,IL-6,IL-1β were decreased(p<0.01),and the activity of MPO was decreased(p<0.01),thus improving the inflammatory injury caused by DSS.In addition,the expression of colonic tight junction proteins(Claudin1,Occludin and ZO-1)in UC mice was increased(p<0.05).Meanwhile,l PS-induced intestinal barrier damage model of Caco-2 cells was established.It was found that PSP significantly increased the expression of tight junction proteins Claudin1,Occludin and ZO-1(p<0.05),indicating that PSP has the ability to repair intestinal barrier damage caused by inflammation in vivo and in vitro.Further studies showed that PSP interferes with the anti-UC effect of TLR4/Myd88/NF-κB pathway by inhibiting the expression of TLR4,Myd88 and NF-κB p65 proteins.2.Improvement effect of PSP on intestinal microflora disorder in UC mice.The significant characteristic of UC is intestinal microbiome disorder.Therefore,16 S r DNA amplicon sequencing technology was used to analyze the cecal contents of mice to study the effects of PSP on the changes of intestinal microbiota species diversity and composition of UC mice.The results of intestinal microflora analysis in each experimental group showed that: After PSP intervention,the decreased α diversity of intestinal flora in UC mice caused by DSS was significantly improved,and the structural composition of intestinal flora was restored.Muribaculaceae has the function of maintaining intestinal homeostasis(p<0.05).The relative abundance of beneficial intestinal flora,including Lachnospiraceae(p<0.01),Ruminococcaceae,Oscillibacter,Lachnoclostridium(p<0.05)and Roseburia,with anti-inflammatory ability,increased.Enterobacteriaceae(p<0.05),Bacteroides(p<0.05),Helicobacter(p<0.01),Parabacteroides,Escherichia-Shigella(p<0.01),Erysipelatoclostridium(p<0.01)and Enterobacter(p<0.01)affect intestinal immune system,and the relative abundance of intestinal pathogens decreased.3.The effects of PSP on metabolites and metabolic pathways of UC mice were analyzed.KEGG analysis of intestinal flora showed that PSP intervention in UC mice may involve several key pathways.PCA,PLS-DA and OPLS-DA were used to analyze metabolites in colon tissue to screen out differential metabolites,and metabolic pathway enrichment analysis of differential metabolites was conducted to clarify the important metabolic pathways of PSP intervention in UC mice.It was found that PSP significantly affected 28 differential metabolites in the intestinal tract of UC mice,and may improve UC through regulating Taste Transduction,m TOR,PI3K/Akt,Fox O and other inflammatory pathways.Meanwhile,molecular docking technology was further used to study the interactions between two major procyanidins and eight metabolites in PSP and key molecular proteins in typical inflammatory related m TOR and intestinal microbiome related TLR4 pathway.Molecular docking results showed that PSP procyanidin trimer PPD and procyanidin A1 and their metabolites both bind to key proteins in uc-related metabolic pathways(m TOR and TLR4),thereby inhibiting their activity.Procyanidin trimer PPD and procyanidin A1 may be one of the key components of anti-UC by intervening m TOR and TLR4 pathways.