Figure 7.

The effects of ERK (A), SMAD (B), and p38 MAP kinase (C) inhibitors on IL-8 production by hardwood and softwood smoke extract. Primary human lung fibroblasts (n = 4) were pretreated for an hour with signaling inhibitors, PD98059 (10 µM), SB431542 (10 µM), and SB239063 (3 µM) in DMSO (vehicle control) for ERK, SMAD, and p38 MAP kinase pathway respectively, then stimulated with 1% hardwood and softwood smoke extract for 24 h. Supernatant was collected and IL-8 concentration analysis was executed via ELISA. Data expressed as the percent of inhibition from control and bars represent mean ± SEM. Statistical analysis executed by using repeated measures, one-way ANOVA with Tukey’s post-test. Significance is represented as * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001