Fig. 1.

Primary human lung fibroblasts (HLFs) upregulate cyclooxygenase-2 (COX-2) expression and produce prostaglandin (PG) E₂, IL-6, and IL-8 in response to activation with IL-1β or cigarette smoke extract (CSE). A: primary HLFs were treated with CSE [0, 16.25, or 32.5 optical density at 320 nm (OD₃₂₀) U/ml] or IL-1β (0, 0.1, or 1 ng/ml), cells were harvested at 72 h after treatment, and COX-2 protein expression was analyzed by Western blotting. B–D: primary HLFs were treated for 24 h (B) or 48 h (C and D) with CSE or IL-1β, and supernatants were analyzed for PGE₂ by enzyme immunoassay (EIA; B) and for IL-8 (C) and IL-6 (D) by ELISA. Values are means ± SD of 3 independent biological replicates per dose. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 vs. untreated (by unpaired t-test).