Comparative study on pathological characteristics of four different antigen-induced rheumatoid arthritis mouse models / 药学学报

ABSTRACT

Rheumatoid arthritis (RA) is an autoimmune disease driven by antigens and mediated by T cells. Collagen II (CII) and fibrinogen (Fib) are the two main antigens in the pathogenesis of RA. The antigen produced after citrulline modification (Cit) is also one of the inducements to induce the body to produce a pathogenic anti-citrulline protein antibody (ACPA). To provide a reference for RA-related research, this study intends to establish an RA animal model by using CII, Cit-CII, Fib, and Cit-Fib antigens, emulsification with complete Freund's adjuvant and immunization with DBA/1 mice, respectively, to compare the pathological characteristics of RA models induced by different antigens from the aspects of pathology, imaging and serum biochemistry. Animal welfare and experimental process are in accordance with the regulations of the Experimental Animal Ethics Committee of the China Academy of Chinese Medical Sciences. The results showed that the CII, Cit-CII, and Cit-Fib induced mice all had symptoms such as joint redness and swelling, and toe deformation and the clinical score and incidence rate were higher than those of the normal group. The CII group had the most serious lesions, with a incidence rate of 100%, and the Cit-CII and Cit-Fib groups had mild symptoms, with a incidence rate of 25% and 37.5%, respectively; pathological and imaging examination results showed that the joints of mice in CII-induced group showed severe synovial inflammation, cartilage and bone destruction, while those in Cit-CII and Cit-Fib group showed only slight inflammatory infiltration, joint cavity stenosis and bone destruction; the results of serum antibody detection showed that CII, Cit-CII and Cit-Fib groups all produced high levels of anti-cyclic citrullinated peptide (CCP) antibodies, among which, Cit-Fib group > Cit-CII group > CII group > Fib group, and both Cit-CII and Cit-Fib groups produced high levels of citrullinated epitope-specific antibodies, while the total IgG level was the highest in CII group; serum ELISA and RT-PCR analysis of joint tissue showed that the expression of pro-inflammatory factors and bone destruction-related molecules increased most significantly in the CII-induced group, followed by Cit-Fib and Cit-CII. The above results showed that among the four different antigens, the symptoms and conditions of arthritis in RA mice induced by CII were the most serious, and IgG instead of anti-CCP antibody was its typical immunological feature, and CII could be the first choice for the model of RA mice; Cit-Fib has certain immunogenicity, can partially induce the symptoms and conditions of RA arthritis in mice, and produce high-level anti-CCP antibody and anti-Cit-Fib antibody, which is more suitable for the study of citrulline-related RA; although Cit-CII has certain immunogenicity, the incidence, and severity of RA arthritis induced by Cit-CII in mice are low.