Evaluation of MMP-3 production in OA and RA FLS. Human fibroblast-like synoviocytes (FLS) isolated from either (a), osteoarthritis (OA), or (b), rheumatoid arthritis (RA) synovial tissues were stimulated with pro-inflammatory cytokine IL-1β (10 ng/ml) in the presence and absence of IDR peptides. Tissue-culture supernatants were monitored for MMP-3 production by ELISA after 24-hour stimulation. Results shown are an average of at least three independent biologic experiments performed with cells isolated from synovial tissues obtained from independent donors ± standard error (*P < 0.05). IDR, innate defence regulator; IL, interleukin; MMP-3, matrix metalloproteinase-3.