Figure 6.

N-Acetylcysteine and EUK-134 attenuate Baltimore PM–induced ROS generation, COX-2 expression, and IL-6 secretion. HBEpCs grown in 35-mm dishes to approximately 90% confluence were pretreated with varying concentrations of N-acetylcysteine (NAC) (0.05, 0.5, and 5 mM) or EUK-134 (0.5, 5, and 25 μM) for 1 hour. In A and D, cells were loaded with 10 μM DCFDA for 30 minutes before addition of Baltimore PM (100 μg/ml) and ROS generation was quantified after 60 minutes using immunofluorescence microscopy. Values are mean ± SD of three independent experiments. *Significantly different from cells treated with vehicle (P < 0.01); **significantly different from cells exposed to Baltimore PM (P < 0.05). In B and E, cells after pretreatment with vehicle or NAC or EUK-134 were challenged with Baltimore PM (100 μM) for 24 hours, and cell lysates (20 μg proteins) were subjected to SDS-PAGE and Western blotted with anti–COX-2 and actin antibodies. Shown are representative blots from three independent experiments. Quantitative analyses from three independent experiments (mean ± SD). *P < 0.05 versus vehicle; **P < 0.05 versus PM challenge. In C and F, media were collected from cells (B and E), and analyzed for IL-6 by ELISA. Values are mean ± SD from three independent experiments in triplicate and represented as pg/ml of medium. *Significantly different from vehicle treated cells (P < 0.05); **significantly different from cells challenged with Baltimore PM (P < 0.001).