Fig. 2

Histologic analysis of joint damage in CIA. (a) Disease controls showed significant increases for all individual histologic parameters of inflammation, pannus, cartilage damage, bone resorption, and periosteal bone formation (p ≤ 0.0001 vs naive animals). At 160 U/kg, RCI significantly inhibited ankle inflammation but had no significant beneficial effect on the other parameters. At 400 U/kg, RCI inhibited all of the histologic parameters except periosteal bone formation. Treatment with ETN alone significantly decreased cartilage damage. When ETN was combined with RCI, further decreases in most histologic parameters were observed. (b) Total summed histopathology score. Disease controls showed significant increases in total histopathology scores (p ≤ 0.0001 vs naive animals). Treatment with ETN alone and 400 U/kg RCI alone significantly decreased total histopathology scores. Greater decreases were seen when RCI and ETN were combined. ^a p ≤ 0.05 vs disease control. ^b p ≤ 0.0001 vs disease control. ^c p ≤ 0.05 vs ETN alone. ^d p ≤ 0.0001 vs ETN alone. Statistics were analyzed by 2-way ANOVA followed by a Newman-Keuls multiple comparisons test. Abbreviations: ANOVA, analysis of variance; CIA, collagen-induced arthritis; ETN, etanercept; RCI, repository corticotropin injection; SEM, standard error of the mean