Figure 3
Effect of exogenous tumor necrosis factor (TNF)-α and interleukin (IL)-1β on fibroblast-mediated collagen degradation. Fibroblasts (4 × 105/ml) were cast into collagen gels and floated in serum-free DMEM to which TNF-α (10 ng/ml) and IL-1β (5 ng/ml) alone or in combination were added in the absence and presence of neutrophil elastase (NE; 20 nM). Hydroxyproline in the gels was determined on day 5. Vertical axis: hydroxyproline content (μg/gel). Horizontal axis: culture conditions. *P < 0.01, compared to control; **P < 0.01 between two groups.