PM2.5 Exposure and Asthma Development: The Key Role of Oxidative Stress

Figure 1

The oxidative and antioxidant imbalance in asthma. In asthma, ROS derived from inflammatory cells (such as epithelial cells, macrophages, neutrophils, and eosinophils) and environmental factors. These inflammatory cells generate amounts of ROS through mitochondrial respiration, NADPH oxidase, and a xanthine oxidase system. The antioxidant enzyme (SOD, CAT, and GPX) activity and the nonenzymatic antioxidants (such as vitamin C, vitamin E, and urate) are reduced in asthma lung. The imbalance regulates various inflammatory factor releases of inflammatory cells, activating inflammatory response and promoting the development and progression of asthma. ROS: reactive oxygen species; NADPH: nicotinamide adenine dinucleotide phosphate; SOD: superoxide dismutase; CAT: catalase; GPX: glutathione peroxidase.