INTERLEUKIN-17 UP-REGULATION OF NITRIC-OXIDE PRODUCTION IN HUMAN OSTEOARTHRITIS CARTILAGE

Objective. To examine the effect of human interleukin-17 (IL-17) on ni tric oxide (NO) production in human osteoarthritis (OA) cartilage unde r ex vivo conditions. Methods. OA cartilage from patients undergoing k nee replacement surgery was used in explant assays to assess the effec t of IL-17. NO production was measured by estimating the stable NO met abolite, nitrite, in conditioned medium. Results. IL-17 augmented the spontaneous production of nitric oxide. This augmentation was sensitiv e to cycloheximide and pyrrolidine dithiocarbamate, but not to dexamet hasone or soluble IL-1 receptor. Conclusion. IL-17 augments nitric oxi de production in OA cartilage via nuclear factor kappa B activation, b ut independently of IL-1 beta signaling.