Presence Of Neutrophil Extracellular Traps In The Blood Of Rheumatoid Arthritis And Correlation Of Degradation Of NETs With Deoxyribonuclease?in Vitro

Objective The aim of this study is to identify the formation and degradation of neutrophils extracellular traps,the effect of drugs on the formation of NETs and determine the activity of deoxyribonucleases?in the patients with rheumatoid arthritis,in order to explore the potential role of NETs and DNase?in the pathogenesis of RA.Method Sixty-five patients from March to November 2016 were recruited for this study,after diagnosis according to the American College of Rheumatology 1982 revised criteria for the classification of RA.30 healthy individuals served as controls.The neutrophils cells separated from the peripheral blood were visualized by Immunofluorescence after stained with fluorescent dyes.Serum samples were tested for the capacities of degrading NETs in vitro.DNase?activity was measured by radial enzyme-diffusion method in serum samples.Correlations between two items were performed with linear correlation analysis.Results1.NETs were visualized with Sytox Green in peripheral blood of 65 RA patients.The content of NETs in peripheral blood of RA patients was significantly higher than that in healthy subjects(35.797% ± 1.606 vs 0.250% ± 0.023,P <0.05);2.NETosis was a dynamic and continuous procedure.NETs consisted of DNA and histones H3;3.The content of NETs in RA was positively correlated with CRP(r = 0.2615,P =0.0354),ESR(r = 0.2564,P = 0.039)and DAS28(r = 0.2456,P = 0.0486);4.The content of NETs pretreated by DXM was significantly lower than that without DXM pretreatment(20.256% ± 1.799 vs 51.061% ± 2.761,P<0.05);5.NETs degradation in RA patients was significantly lower than that in healthy subjects(47.430% ± 7.708 vs 94.189% ± 4.676,P <0.05);6.Serum DNase?activity in RA patients was significantly lower than that in healthy subjects(0.346 ± 0.136 U / ml vs 0.489 ± 0.168 U / ml,P <0.05);7.Serum DNase?activity in RA was negatively correlated with CRP(r =-0.3250,P= 0.0155)and ESR(r =-0.2837,P = 0.0358);8.Serum DNase?activity was positively correlated with NETs degradation in the serum of RA patients(r = 0.5610,P = 0.0001,n = 35).Conclusion This clinical study vividly demonstrates the formation and degradation of NETs in RA and generally confirms the effect of serum Dnase1 activity on NETs degradation.Dexamethasone can interfere with the formation of NETs.At the same time,after performing the correlation analysis,we realize that the content of NETs and serum Dnase1 activity are related to disease activity.The research shows that NETs plays an important role in the pathogenesis of RA as well as disease development.In addition,our study expands the targeted therapy of RA from the aspects of NETs formation and degradation.