Non-invasive screening of progressive joint defects in the Type II collagen-induced arthritis animal model using radiographic paw images

ObjectiveThis study presents a method for non-invasive screening of progressive arthritic reactions in a representative rheumatoid arthritis (RA) animal model of Type II collagen-induced arthritis (CIA).MaterialsSeventeen male DBA/1J mice (9 weeks old) were used for the control group (seven) and the CIA group (ten).TreatmentThe CIA model was induced by the injection of a Type II collagen and incomplete Freund’s adjuvant emulsion.MethodsArthritic reactions including joint space narrowing (JSN), bone erosion, inflammation, and physiological defects were observed using five non-invasive methods. The degrees of JSN and bone erosion were quantified using macro-radiographs of specific joints and bones, while the severity of inflammation was evaluated by changes in paw volume and visual scoring of edema and erythema.ResultsSignificant differences were observed in JSN (≤48.29%, p < 0.0001), bone erosion (78.30%, p < 0.0001), grip strength (p < 0.05), and inflammation (91.67% in edema and 194.12% increase in paw volume, p < 0.001) between the CIA group and the controls. The relationships between factors exhibited significant positive correlations (R ≥ 0.9229, p < 0.05) between radiographic parameters, with symmetries of ≥0.9062 (p < 0.05) for JSN and ≥ 0.8575 (p < 0.001) for bone erosion, 0.8770 (p < 0.0001) for inflammatory parameters, and ≥0.9527 (p < 0.0001) for radiographic and non-radiographic parameters.ConclusionsOur non-invasive radiographic and non-radiographic methods of documentation were both acceptable for screening joint defects during RA progression. In addition, the results of this study may be useful for monitoring the progression of joint pathology in RA diseases.