Effects of interleukin (IL)-1ra on peripheral blood-macrophage-conditioned medium (PB-MCM)-induced signaling in chondrocytes. Chondrocytes were untreated (CL) or stimulated with PB-MCM for the indicated periods (t). The results are the mean ± SEM of three to four separate experiments and show the effects of IL-1ra on PB-MCM-induced JNK and Akt phosphorylation (A, t = 10 min) and NF-κB activation (B, t = 1 hour), respectively. Before culturing under control conditions (CL) or stimulation with PB-MCM, the PB-MCM and chondrocytes were preincubated with 1 × PBS or IL-1ra for 2 hours. *P < 0.05 versus CL. #P < 0.05 versus PBS-treated cells under PB-MCM stimulation.