Figure 1.

IL-1β-induced prostaglandin E₂ release and COX-2 mRNA and protein levels in canine synovial fibroblasts. Cells treated with (closed circle) or without (open circle) canine recombinant IL-1β (100 pM) showed an increase in prostaglandin E₂ (PGE₂) release (A) and COX-2 mRNA levels (C) in a time-dependent manner, but did not affect COX-1 mRNA levels (E). Cells were treated with the indicated concentrations of IL-1β for 48 h (B) or 6 h (D) and assayed for PGE₂ release (B) and COX-2 mRNA levels (D) in a dose-dependent manner. Cells treated with IL-1β (100 pM) for 0–48 h showed increased protein levels of COX-2 in a time-dependent manner (F; first row), but did not affect the protein levels of COX-1 (F; second row). The expression of COX-2 (G) and COX-1 (H) in IL-1β-stimulated cells were compared with the expression at 0 h. Results have been represented as mean ± standard error (SE) from biological triplicates. *P < 0.05. Cell lysates (10 μg protein) were used for immunoblotting. β-actin was used as the internal standard (F; third row).