Changes in serum antibodies and joint inflammation of collagenII-induced arthritis in rats

Objective: To establish the bovine collagenⅡ(CⅡ)-induced arthritis(CIA)rat model and investigate the pathological characteristics and dynamic changes of serum antibodies.Methods:SD Rats were used to establish CIA model by multi-dot intradermal injection of 150 μg of CⅡ emulsified in complete Freund′s adjuvant(CFA) at the rat tail base on d 0 and d 10,respectively.The degree of swelling and arthritis score were evaluated.The levels of serum antibodies such as IgG, IgG and IgM type rheumatoid factors(RF),and anti-CⅡ antibody were detected by ELISA.Synovial histopathology and imaging changes were observed through roentgenography.Results: The incidence of arthritis in model group was 100% and the peak of joint swelling was achieved on d 23 after immunization.On d 30 soft-tissue swelling and bone destruction were prominent.On d 60 bone destruction was more prominent,periosteal new bone formation appeared,and typical arthritis pathology with chronic proliferative synovitis and secondarily destroyed articular cartilage and bone were found.The serum levels of antibodies such as IgG,IgG RF,IgM RF and anti-CⅡantibody were significantly higher than those in the normal control on d 15,and then remained at the higher levels.Conclusion: The CIA rat model was successfully established and the pathological changes of arthritis occurred on d 12 after the first immunization and persisted at least till d 72.