| BackgroundRheumatoid arthritis(RA)is a common chronic systemic autoimmune disease.It is characterized by synovitis gradually spreading to the joint capsule and surrounding cartilage and bone tissue,resulting in joint pain,stiffness,deformity,and loss of function.Destruction of the synovial joint can lead to severe disability and premature death.Although the etiology of RA remains to be elucidated,it is currently believed that the development of RA requires both genetic and environmental factors.Genetic studies in patients with rheumatoid arthritis have identified multiple genetic risk sites,but have failed to accurately predict disease occurrence.In terms of the environment,the relationship between intestinal microbiota and RA has attracted more attention.Imbalance of intestinal microbiome is a change in commensal bacteria in the small intestine and colon,and is one of the important environmental factors related to the pathogenesis of RA.To explore the role of intestinal microbiota in the pathogenesis of RA,understanding the effect of gut microbiota on the intestinal immune and autoimmune responses to RA,will provide a new insight for the diagnosis and treatment of RA.Previous research in our laboratory has analyzed the intestinal microbiota between RA patients and normal individuals.It was found that the intestinal microbiota of RA patients was dysregulated with high abundance of Enterococcus faecium and Lactobacillus berivis compared with normal individuals.In addition,wehave successfully isolated these two bacteria from the stool samples of RA patients.In order to further study the mechanism of the two bacteria acting on RA,we cultured these two bacteria in vitro and established AA rat model.Rats were treated with bacteria,thereby to investigate the effects of these two bacteria on the intestinal flora,intestinal barrier,intestinal immunity and autoimmunity of arthritic rats.ObjectiveEstablishing arthritis rat model,and then treated with isolated bacteria Enterococcus faecium and Lactobacillus berivis,to explore the relationship between intestinal microbiota and RA.Methods1.Using different media cultured Enterococcus faecium and Lactobacillus berivis isolated from stool samples of RA patients.2.Wistar rats were randomly divided into 4 groups,Normal,AA,AA+E,AA+L,after one week adaptive culture,AA,AA+E,AA+L were injected with Freund's complete adjuvant 10mg/ml,0.1ml per rat,and then each group of rats was administered with different bacteria every day.After 24 days,rats were sacrificed,the intestinal mucosa,colon tissue,and ankle joints were collected.3.The arthritis severity of the rat was evaluated with a grading system.The intestinal mucosal bacteria in each group was analyzed by 16sDNA;histopathological observation of ankle joint and colon tissue in each group were determined by H&E;the expression of tight junction proteins was detected with immunofluorescence;the expression of inflammatory factors in colon tissue and ankle joint was measured by q-PCR and IHC.Results1.It was found that the arthritis of AA+E and AA+L group was significantly serious than that of AA group.2.After bacterial administration,the abundance and diversity of intestinal mucosa inAA+E and AA+L groups were significantly lower than those in AA group and Normal group,and intestinal microbiota was imbalanced.3.The colon tissue of AA+E and AA+L groups was occurred pathological damage,joint tissue was also destructed,and the expression of inflammatory factors in colon tissue and joint tissue was higher than that in AA group and Normal group.Conclusion1.Enterococcus faecium and Lactobacillus berivis isolated from the intestinal microbiota of RA patients can aggravate the progression of rheumatoid arthritis,causing joint swelling and damage.2.The pathogenic mechanism is related to the intestinal barrier including physical barrier,biological barrier,immune barrier damage,and changes of the systemic immune system caused by intestinal microbiome imbalance.These results provide a new idea for clinical diagnosis and treatment of RA. |
PDF Full Text Request