Fig. 4.

The effect of alternative culture conditions on dexamethasone inhibition of LPS stimulated TNF-α release. Macrophages from smoking controls (A and C; n = 9) and COPD patients (B and D; n = 10) were cultured under condition 1 (white bar) or condition 2 (grey bar), pre-treated with vehicle control (0.005% DMSO) or dexamethasone (0.1–1000 nM) for 1 h before being stimulated with LPS (1 μg/ml) for 24 h. Culture supernatants were analysed for TNF-α. Data shown are mean ± SEM of absolute TNF-α levels (A and B) or percentage inhibition of TNF-α (C and D). *, **, and *** = significant mediator reduction below vehicle control (p < 0.05, p < 0.01, and p < 0.001 respectively) (A and B) or significantly higher level of inhibition compared to respective dexamethasone concentration under condition 1 (C and D).