Figure 2. Effects of positive pressure and rhIL-1 on the secretion of MMP-1, MMP-2, MMP-3, and PGE₂. (A,B) Odontogenic keratocyst fibroblasts (2 x 10⁴ cells/cm²) (a) and odontogenic keratocyst epithelial cells (4 x 10⁴ cells/cm²) (b) were seeded alone or co-cultured (c), and then incubated in serum-free DMEM for 24 hrs at 37°C under atmospheric pressure or 80 mm Hg of positive pressure. IL-1ra was added 15 min before the application of positive pressure. (C,D) Odontogenic keratocyst fibroblasts (a) and odontogenic keratocyst epithelial cells (b) were incubated in serum-free DMEM for 24 hrs at 37°C in the absence or presence of rhIL-1. (A,C) The culture media (200 µL) were concentrated and subjected to Western immunoblotting for MMP-1 and MMP-3, and the 30-µL culture media were subjected to gelatin zymography. (B,D) The concentration of PGE₂ in the culture media was measured by ELISA as described in MATERIALS & METHODS. Vertical bars indicate mean ± SD (n = 4). *Significant difference at p < 0.05.