Fig. 8.

A–E: effect of ozone exposure on lung IL-13, keratinocyte-derived chemokine (KC/CXCL1), IFN-γ, heme-oxygenase-1 (HO-1), and caspase-3 gene expression measured by RT-PCR. The expression of IL-13, KC, IFN-γ, and caspase-3 was increased significantly after 6 wk of ozone (n = 8) compared with air-exposed controls (n = 4), with nonsignificant increases in these genes at 3 wk (n = 4). HO-1 gene expression decreased after 3 and 6 wk of ozone exposure, reaching significance at 6 wk. There was no significant effect on these genes after 1 exposure to ozone (n = 4), although there was a nonsignificant increase in KC and HO-1. Data are expressed as means ± SE. *P < 0.05, **P < 0.01, ***P < 0.001.