Local effects of intra-articular injection of anti-rabbit tumor necrosis factor alpha monoclonal antibody in antigen-induced arthritis of the rabbit temporomandibular joint.

BACKGROUND: Local effects of intra-articular (IA) injection of anti-rabbit tumor necrosis factor alpha monoclonal antibody (anti-TNFα mAb) for antigen-induced mono-arthritis (AIA) of the rabbit temporomandibular joint (TMJ) and its systemic influences were evaluated.

METHODS: Biochemical analysis of synovial fluid (SF), clinical and histopathological analyses of TMJ, and serum analysis were performed after inducing AIA in bilateral TMJs of 40 New Zealand White rabbits. IA injection of anti-TNFα mAb in unilateral TMJ (TNF blockade side; n = 12) and IgG (n = 12) was performed while saline injected on the contralateral side. TNFα and IL-1β in SF was analyzed at Days 1, 3, 7, and 21. Joint swelling and head withdrawal reflex threshold (WRT) over TMJs were evaluated in TNF blockade side (n = 12) with histopathological analysis at Days 3, 7, and 21. In remaining four animals with TNF blockade, TNFα and anti-TNFα mAb in serum were analyzed.

RESULTS: Tumor necrosis factor alpha in SF was significantly lower in TNF blockade side on all days but IL-1β was lower only on Day 3. WRT was significantly higher at all times in the blockade side. Less inflammatory reactions and degenerative changes of cartilage were observed on Days 7 and 21 in the blockade side. TNFα and anti-TNFα mAb were under detection level in serum at all times.

CONCLUSIONS: Intra-articular injection of anti-rabbit TNFα mAb in mono-arthritis model was effective to control local inflammation and degenerative joint changes. Further, low-dose IA injection of antibody may not have systemic side effects.