Figure 8
Analysis of mitochondrial damage. (A) ROS and mitochondria co-localization was assessed by fluorescence microscopy. BEAS-2B cells, exposed for 2 h to 7.5 μg/cm2 of winter PM2.5 and to its organic fraction, were stained for DNA, ROS and mitochondria. Co-localization signal of ROS and mitochondria was measured by Axiovision Rel 4.8 software as reported in materials and methods. (B) Mitochondrial damage in BEAS-2B cells exposed for 24 h to 7.5 μg/cm2 of winter PM2.5 was assessed by fluorescence microscopy (B1) and flow cytometry (B2). Flow cytometry results are reported as fluorescence arbitrary units (mean ± SEM of 3 independent experiments). Carbon black (CB) was used as reference control for carbonaceous particles effects. (C) Mitochondrial superoxide formation in BEAS-2B cells exposed for 2 and 24 h to 7.5 μg/cm2 of winter PM2.5 was assessed by fluorescence microscopy (C1) and flow cytometry (C2). Flow cytometer results are reported as fluorescence arbitrary units (mean ± SEM of 3 independent experiments). Hydrogen peroxide (1 mM) was used as positive control and reported 3.4 ± 0.11 and 12.6 ± 0.09 as fluorescence arbitrary units at 2 and 24 h, respectively. * Statistically significant difference from untreated cells (control), P < 0.05.