Specific inhibition of IL-1Ra production by dexamethasone. (a) Freshly isolated chondrocytes were stimulated with 1 ng/ml IL-1β, 10 ng/ml IL-6 and 100 ng/ml sIL-6R for 72 hours in the absence (black bars) or presence (white bars) of 10-7 M dexamethasone. *P < 0.001 versus control without dexamethasone, †P < 0.001 versus IL-1β, IL-6 and sIL-6R without dexamethasone. (b) Proteoglycan content was measured in the culture supernatants used for IL-1Ra determination. *P < 0.01 versus control without dexamethasone.