[Implication of oxidant stress in airway inflammation].

There are many species of oxygen radicals in the environment. Inflammatory cells also produce many oxidants in biological tissues. The lung is constantly exposed to highest content of oxygen in the body, and frequently exposed to tobacco smoke, industrially polluted air, and exhausted gas. These conditions make the airway to be exposed to oxygen radicals, and may lead to subsequent oxidant stress and tissue injury, when the stress overwhelms the antioxidant system. Oxidants may also regulate expression of several proinflammatory cytokines with interacting with transcription factors. There is increasing evidence that COPD is related to airway oxidant stress. Measurement of some exhaled gas contents may be useful to monitor ongoing inflammation/oxidant stress and subsequent lipid peroxidation in COPD.