Fig. 4

Histologic and radiographic analysis of joint tissues of AIA rats. A Images of H&E staining, Safranin O staining, and radiography of joints in (a) control rats, (b) control rats treated with vehicle, (c) AIA rats, (d) AIA rats treated with TAK-242 (3 mg/kg), and (e) AIA rats treated with TAK-242 (5 mg/kg). In H&E staining, the AIA group showed pannus formation (PF) and focal erosion (FE). TAK-242 treatment (5 mg/kg) exhibited normal JS and resolved PF and FE. Consistent with H&E staining data, Safranin O staining showed that the AIA group had extreme cartilage degradation; TAK-242 treatment (5 mg/kg) inhibited the extreme cartilage degradation (red arrow). In contrast, TAK-242 treatment at a dose of 3 mg/kg did not affect the reduced joint space (red arrow) and cartilage degradation (black arrow). Radiographic images of ankle and knee joints from representative rats on day 21 show no differences between groups. B The graph denotes the mean score of joint space, pannus formation, cellular infiltration, and cartilage degradation based on a 4-point scale (0 = normal, 1 = mild, 2 = moderate, 3 = high, and 4 = extreme). ***P < 0.001 compared with control. ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 compared with arthritic model