Interleukin 17 induced nitric oxide suppresses matrix synthesis and protects cartilage from matrix breakdown.

Objective: To investigate the role of nitric oxide (NO) in basal and cytokine induced cartilage matrix breakdown and synthesis across different species and in chondrocytes cultured as isolated cells or as tissue explants.

Methods: Articular cartilage from bovine, porcine, or human joints was cultured as explants in serum-free media. Explants or monolayer cultures of primary chondrocytes were treated with cytokines in the absence or presence of inhibitors [antibodies to leukemia inhibitory factor (anti-LIF) or tumor necrosis factor-alpha, dexamethasone, or inhibitors of aggrecanase or NO synthase].