Figure 1
Effect of PM 2.5 -AW exposure on human bronchial epithelial cells. (A) Dose response of DiOC6(3) (to measure the mitochondrial ΔΨm drop), hydroethidine (HE, ROS-sensitive dye), Annexin V-FITC (for phosphatidylserine exposure) and the propidium iodide (PI, as a plasma membrane permeabilization marker) staining after 24 hours exposure of 16HBE bronchial epithelial cells to PM2.5-AW (1-50 μg/cm2) or H2O2 (500 μM). (B) Kinetic study of PM2.5-AW effect on apoptosis. 16HBE cells were exposed to PM2.5-AW (1 to 50 μg/cm2) or H2O2 (500 μM) for 48 h or 72 h before flow cytometric analysis of cells presenting simultaneously a mitochondrial depolarization (DiOC6(3) low) and a superoxide anion generation (HE -> Eth high). Results are representative of three independent experiments. (C) Subconfluent bronchial epithelial cell lines NCI-H292, BEAS-2B and primary bronchial epithelial cells (NHBE) were exposed 24 h to 1-50 μg/cm2 PM2.5-AW, and H2O2 (1 mM) before flow cytometric analysis of cells presenting simultaneously a DiOC6(3) low and PI high staining. (D) Human bronchial epithelial cells 16HBE, NCI-H292, BEAS-2B or NHBE were exposed 24 hours to 10 μg/cm2 of different batches of PM2.5 (Auteuil-Winter (AW), Auteuil-Summer (AS), Vitry-Winter (VW) or Vitry-Summer (VS) corresponding to two locations of Paris: (i) a school playground at Vitry-sur-Seine in a suburb of Paris and (ii) Porte d'Auteuil adjacent to a major highway). Then, cells were analyzed as previously described. Data are represented as mean ± SD (* treated vs. control, p < 0.05, n = 3).