Interleukin (IL) 1ß dose and time response study of matrix metalloprotease 13 (MMP-13) production (A) and expression (B) in the presence or absence of licofelone. Human osteoarthritis chondrocytes were incubated for (A) 24 or 72 hours, or (B) 24 hours with or without 1–100 pg/ml IL1ß or 3 µg/ml licofelone. MMP-13 production was determined in the conditioned medium using a specific enzyme linked immunosorbent assay (ELISA) (A), and MMP-13 expression was determined by real time polymerase chain reaction (B). (C) Licofelone dose and time response study of MMP-13 production. Human osteoarthritis chondrocytes were incubated for 24 to 96 hours in the absence or presence of 100 pg/ml IL1ß and 0.3, 1.0, or 3.0 µg/ml licofelone or NS-398 at 10 µM and Bay-X-1005 at 10 µM. MMP-13 production was determined in the conditioned medium using a specific ELISA. Data are expressed as means of (A) four, (B) six to seven, and (C) four independent experiments. Error bars = SEM; p values indicate significant differences from the respective controls.