The Mechanism Of Angelica Sinensis Polysaccharide Improving Rheumatoid Arthritis In Rats

Rheumatoid arthritis(RA)is a chronic autoimmune disease with a high incidence,characterized by synovial hyperplasia,inflammatory cell infiltration,pannus formation,articular cartilage,and bone matrix destruction.RA negatively impacts the life quality of patients and may lead to irreversible disability if left untreated,which brings physical and mental burdens to people.Recent studies have demonstrated that diet can contribute to the development and progression of RA.Indeed,non-starch polysaccharides(NSPs)were known to be related to the improvement of RA.Angelica sinensis polysaccharide(ASP),the main component of Angelica sinensis,can enter the large intestine,be utilized by the intestinal flora,and have excellent biological activity.Some studies have reported the potential of ASP in improving RA,but it is not clear whether ASP can modify intestinal flora,intestinal function,and metabolism to alleviate RA.In this study,we established collagen-induced arthritis RA and treated CIA rats with 200 mg/kg(L),400 mg/kg(M),or 800 mg/kg(H)ASP for intragastric intervention.The intestinal microbial differences between the control,CIA,and ASP intervention groups were compared.The transcriptome was applied to analyze the functional changes in the colon of rats caused by ASP intervention.The metabolite composition differences of cecum contents in were also analyzed.Our results showed:(1)ASP alleviated RA.The paw volume and the levels of type Ⅱ collagen antibodies and tumor necrosis factor-α(TNF-α)were significantly reduced(p < 0.05),high dose may have better effectiveness.Compared with Mod group,the paw swelling of high-dose ASP group was significantly reduced by 16.70%;CⅡ-IgG,CⅡ-IgG1,CⅡ-IgG2 a,CⅡ-IgG2 b,TNF-α were reduced by 18.68%,13.18%,15.92%,14.50%,13.58%.(2)ASP affected the composition of the intestinal flora of CIA rats.The potential RA-improved bacteria were increased,such as Lactobacillales,norank＿f＿＿norank＿o＿＿Clostridia＿UCG-014,.Several bacteria may be involved in the development of RA were decreased,such as norank＿f＿＿Oscillospiraceae and norank＿f＿＿Desulfovibrionaceae.(3)The colonic transcriptome showed that ASP could restore RA-induced intestinal dysfunction,such as tight junction disorder.ASP upregulated Cldn5,a gene encoding the tight junction protein Claudin-5,then impaired the intestinal barrier and cell polarity.The expression of Slit3 and Rgs18,two genes related to osteoblast differentiation,were increased to alter the balance between osteoblasts and osteoclasts to reduce RA.It is also possible that a combined effect of bacterial and gene expression may have contributed to the RA improvement.(4)ASP can repair the metabolic disorder caused by RA in rats.ASP can regulate lipid metabolism disorder in CIA rats to relieve inflammation,and up-regulate the relative contents of metabolites Pfaffic acid and Beta-Thujaplicin with anti-rheumatic ability.In summary,our study demonstrated that ASP alleviated RA,which may be achieved through the gut-joint axis.ASP alters the relative abundance of key bacteria associated with RA symptoms(Lactobacillales,norank＿f＿＿norank＿o＿＿Clostridia＿UCG-014,norank＿f＿＿Oscillospiraceae,and norank＿f＿＿Desulfovibrionaceae).ASP also restored RA-induced dysregulation of colonic gene expression and promoted the expression of Cldn5,encoding a tight junction-related transmembrane protein,to strengthen the intestinal barrier and reduce the passage of immune cells.In addition,ASP enhanced the expression of Slit3 and Rgs18,two proteins that inhibit osteoclast differentiation and promote bone formation,thereby improving RA.In addition,ASP modified the content of metabolites with the anti-RA ability and the metabolic pathway involved in inflammation development.Therefore,our study serves as a foundation for further investigation of the gut-joint relationship and the prevention or treatment of RA with dietary treatments.