Chronic immune synovitis in rabbits. I. Immunoglobulin and beta-glucuronidase analyses of synovial tissues and joint exudates.

Immunoglobulin and beta-glucuronidase levels in joint exudates and homogenates of synovial tissues were measured during the course of bovine serum albumin (BSA) antigen-induced synovitis in rabbits. After intra-articular BSA challenge, the anti BSA hemagglutinating antibody in tissue homogenates increased with time up to 14 days. Results obtained indicated relatively greater increases in specific anti-BSA activity compared with total IgG and are compatible with in vivo antibody synthesis by inflamed synovial tissue. beta-Glucuronidase was measured as a reflection of phagocytic cell activity. Tissue enzyme levels increased to a maximum at 1 day and this level persisted up to at least 7 days, despite the fact that exudate enzyme levels reached a maximum at 1 day and then declined significantly over the next 2-3 weeks. These observations reinforce the view that inflamed synovial tissue possesses a substantial potential for perpetuating joint destruction by producing increased levels of inflammatory mediators.