Dose-dependent therapeutic effects of the STAT-1 decoy oligodeoxynucleotide (ODN) on antigen-induced arthritis (AIA). Arthritis was induced in the right knee joint at day 0, 4 h after application of the decoy ODN. (a) Effects of the STAT-1 decoy ODN treatment on joint swelling. Joint swelling was assessed as the difference between right (arthritic) and left (untreated) knee joint diameter. (b) Histological evaluation of arthritis (day 14 of AIA). Hematoxylin-eosin stained knee sections were evaluated blindly by grading of inflammation (infl.; cell exudate or infiltrate, hyperplasia) and joint destruction (destr.; necrosis, erosion and pannus formation). Total arthritis score (arthr.) is defined as the sum of the inflammation and destruction scores. Each ODN dose represents n = 10;#P ≤ 0.05, ##P ≤ 0.01 (0.25 nmol versus buffer-treated AIA control); *P ≤ 0.05, **P ≤ 0.01, (1.25 nmol versus buffer-treated AIA control); +P ≤ 0.05, ++P ≤ 0.01, +++P ≤ 0.001 (10 nmol versus buffer-treated AIA control).