Fig. 2

Effect of treatment with methotrexate (MTX) on clinical and functional parameters. a Clinical score of naïve (n = 16, blue circles), complete Freund’s adjuvant (CFA) (n = 15, green circles), untreated collagen-induced arthritis (CIA) (n = 21, incidence 87.5%, red triangles), and MTX-treated CIA mice subgrouped in poor responders (arthritis improvement score (AI score) < 20, n = 6, white squares), mild responders (20 < AI score < 70, n = 6, dashed squares), and high responders (AI score > 70, n = 11, black squares). The asterisk symbol is used for comparison with the naïve, CFA, and MTX high responder groups, and the plus sign for comparison with the MTX mild responder group. b Representative 3D reconstruction images of hind paws in each experimental group at D50. Note joint destruction and bone degradation (“black” areas in bone structure) only in untreated CIA and MTX poor responder mice (arrows). c Ankle bone degradation measured as the relative BS/BV ratio quantified in micro-CT images. The asterisk symbol is used for comparison with the CFA group, the plus sign for comparison with the MTX mild responder group, and the dollar sign for comparison with the MTX high responder group. d Histological score measured in naïve (n = 10 paws), CFA (n = 9), untreated CIA (n = 20), MTX poor responder (n = 6), MTX mild responder (n = 5), and MTX high responder mice (n = 9). *^,+,$p < 0.05, **^,++,$$p < 0.01, ***^,+++,$$$p < 0.001