The Relationship Between Intestinal Flora And Rheumatoid Arthritis

Research backgroud:Rheumatoid arthritis (RA) is an autoimmune disease that showed chronic synovitis,widely destruct of articular cartilage, joint deformity and loss of function. RA mainlysymmetrical occurred in fingertip and wrist and other small joints in early onset of thedisease, it made body mistakenly attack by own immune system through complementsystem activated by autoimmune reaction and forming immune complex whichdominated by the rheumatoid factor. RA is the most common inflammatory jointdisease in the clinical, causing painfully stiff and having a long disease period, to date,there is no known cure for rheumatoid arthritis. The pathology of RA is complex andhas not been fully clarified, it was considered that a complex interaction betweengenetic and environmental factors. Recent researches implicated that intestinal floraimbalance maybe a very important role in RA development. Studies showed thatintestines dysbacteriosis presented in the RA animal model and intestines microbiotachanged in RA patients. The development of immune system and immune tolerance isclose related to gut flora colonization. Intestinal flora imbalance resulted in rheumatoidarthritis development through altered intestinal epithelium and mucosa permeabilitywhich made immunological tolerance defection, sensitized immune cells and allergensrecruit in joints. However, the research in this field has just started, and it is not certain whether the flora imbalance is a startup factor or a passive product for RA. Whetherthere are specific characteristics in the intestinal flora imbalance of RA patients, howdoes flora imbalance actually influence the occurrence and development of RA, and thescreening of bacteria playing a key role during the course of RA are all urgent tasks tobe further solved.Objective:1. To contrast analyze gut bacteria diversity and flora characteristics in rheumatoidarthritis patients and healthy subjects, and discussion the influence of intestinesdysbacteriosis to rheumatoid arthritis.2. To explore the main flora which influence the development of rheumatoid arthritisand its significance in treatment of the disease.Methods:1. According to RA classification criteria from American College of Rheumatology(ACA), fecal samples were collected from rheumatoid arthritis patients and healthysubjects, then we tested those samples which reflect the population of gut bacteria.2. Immunoturbidimetric Assays was used for the diagnosis of rheumatoid factor forrheumatoid arthritis patients.3. PCR-DGGE fingerprinting was used to analyze the changes of gut bacteria betweenrheumatoid arthritis and healthy subjects, and sequencing method was used toanalyze specific bands.Results:1. Compared with the normal control group, rheumatoid factor in rheumatoid arthritisgroup was significantly increased (P<0.01).2. Compared with the normal control group, the abundance of intestinal flora inrheumatoid arthritis group was reduced (P<0.01).3. From clustering and PCA analysis, the normal control group and rheumatoidarthritis group formed two obviously clusters.4. Sequence analysis showed that five lighter bands from DGGE gels of normalcontrol group and rheumatoid arthritis group. Band1-5exhibited respectively high similarities with those from pelobacter venetianus (88.15%) belong to theProteobacteria, pevotella copri(95.36%) belong to the Bacteroides, dalistersuccinatiphilus(94.33%) belong to the Firmicutes, sgella sonnei(100%) belong tothe Proteobacteria and sutterella sp.(96.4%) belong to the Firmicutes. Band1andband4were mainly tested in rheumatoid arthritis intestines, and band2and band5mainly presented in normal control intestines, band3were appeared in bothintestines.Conclusion：1. Intestinal flora imbalance and reduced diversity of microbiota were appeared in thepatients with rheumatoid arthritis.2. Shigella and Venetianus were appeared in the intestinal flora of rheumatoid arthritispatients accompanied with increased opportunistic pathogen and reduced normalflora.3. Intestinal flora imbalance is related to the pathogenesis of rheumatoid arthritis.