IL-1β stimulates the production of nitrite and PGE
release. Temporal profile of IL-1β on the production of (a) nitrite and (b) PGE2 release by chondrocyte/agarose constructs cultured under free-swelling conditions with 0 or 10 ng/ml IL-1β and/or 10 μmol/l SB203580. Bars represent the mean and standard error of the mean of six replicates from three separate experiments. Two-way analysis of variance with post hoc Bonferroni-corrected t-tests was used to compare data under the different treatments: *P < 0.05 and ***P < 0.001 for comparisons between time zero with IL-1β; +P < 0.05, ++P < 0.01 and +++P < 0.001 for comparisons between untreated with IL-1β or IL-1β with IL-1β plus SB203580. PG, prostaglandin.