The Mechanism Of CXCR4 Receptor In Rheumatoid Arthritis-associated Interstitial Lung Disease

ObjectiveChemokine receptor CXCR4 is involved in various inflammatory diseases mediated by peripheral blood immune cells,including rheumatoid arthritis(RA),interstitial lung diseases(ILD)and inflammatory bowel disease.Rheumatoid arthritis(RA)is a kind of chronic diseases associated with joint disease and autoimmune disorders.For RA patients,ILD is one of the most common and most severe extraperitoneal lesions.Studies have shown that CXCR4 and its ligands mediate the infiltration of immune cells into joints and lung tissues.At present,there are many clinical reports on RA-associated ILD(RA-ILD),but the report on the pathogenesis of RA-ILD is very few and the lack of suitable animal disease model is one of the reasons.This study first established the mouse collagen-induced arthritis(CIA)model,and further found that the occurrence and development of mouse arthritis,and can lead to the production of pulmonary inflammation,so that the mouse CIA model can as an animal model for studying RA-ILD.Secondly,a murine lymphocyte CXCR4 condition knockout(CKO)model was established.CIA model was established on the basis of CKO mice.Studying the pathogenesis of CXCR4 in RA-ILD.Method(1)CXCR4flox/flox genotype mice and Mx1-cre genotype mice were crossed to obtain CXCR4flox/+/Mx1-cre genotype mice.And CXCR4flox/+Mx1-cre genotype mice were used as parents for a new round of selfing and breeding to obtain CXCR4flox/flox/Mx1-cre genotype mice by PCR.(2)The genetic model of lymphocyte CXCR4 CKO was established on the CXCR4flox/flox/Mx1-cre genotype mice by injecting PI:PC.(3)CIA model was established on healthy wild-type C57BL/6 mice by injection of emulsion which was a mixture of chicken type ? collagen and complete Freund's adjuvant,and the lesions of mouse joint and lung tissue were analyzed.(4)CIA model was established on lymphocyte CXCR4 conditioned knockout mice,and the changes of joint and lung tissue were analyzed,and the changes in the number and proportion of T and B lymphocytes were analyzed by flow cytometry.Results(1)CXCR4flox/flox/Mxl-cre knockout mice were successfully obtained for CXCR4 knockout of peripheral blood lymphocytes.(2)The CXCR4 CKO mouse model of peripheral blood lymphocytes was successfully constructed on the CXCR4flox/flox/Mxl-cre genotype mice after injection of PI:PC.(3)The mouse CIA model was successfully established by immunizing wild-type mice with complete Freund's adjuvant(CFA)and Chicken Type II Collagen,and found that the lungs of CIA model showed inflammation of lymphocytes.(4)Compared with the control group,the hyperplasia of synovial membrane and the infiltration of inflammatory cells in the tissues around joint of the mice with CXCR4 CKO lymphocytes were inhibited.At the same time,the infiltration of inflammatory cells in lung tissue and the expression of inflammatory factors were both significantly decreased.The results showed that the knockout of CXCR4 in lymphocytes not only relieves arthritis in CIA mice,but also decreases the inflammation of lung tissue in CIA mice.(5)During the pathogenesis of CIA mice,T lymphocytes in the control group had a significant increase in the peak period,decreased from the peak to the recovery period,and marked changes did not appear in CXCR4 knockout mice.The number of B lymphocytes in the control group was significantly decreased at the peak stage,and increased from the peak to the recovery period,while the B lymphocytes of the CXCR4 knockout mice did not decrease significantly.ConclusionsMouse CIA model not only can be used to study RA,but also can be used as an animal disease model for studying RA-ILD.Peripheral blood T lymphocytes and B lymphocytes are involved in the pathogenesis of RA-ILD,and CXCR4 mediated peripheral blood lymphocytes play a critical role in the occurrence and development of RA-ILD.