PM10 impairs the antioxidant defense system and exacerbates oxidative stress driven cell death

The aim of this study was to investigate the effect of airborne particulate matter with a mean aerodynamic diameter of ≤10 μm (PM10) on oxidative stress markers and antioxidant enzymatic activity and its relevance in the face of acute oxidative challenge in a human lung epithelial cell line (A549). PM10-induced reactive oxygen species (ROS) generation and oxidative damage with no changes in cellular viability. In addition, PM10 decreased glutathione (GSH) levels (54.9%) and the activity of the antioxidant enzymes superoxide dismutase (65%), catalase (31.2%), glutathione reductase (61.5%) and glutathione-S-transferase (42.39%). Trolox, a scavenger of reactive species, prevented the increase of ROS generation and the decrease in GSH levels but partially prevented PM10-induced oxidative damage. Interestingly, it was unable to avoid the decrease in the activity of antioxidant enzymes. Finally, the survival of the cells previously exposed to PM10 and challenged with hydrogen peroxide was significantly lower. We conclude that the impairment in the antioxidant defense system induced by PM10 weaken ROS detoxification which exacerbates cell death when these cells are exposed to an acute oxidative challenge.