Impact of environmental factors on lung defences

摘要

The lungs are one of the most important organs exposed to environmental agents. The lungs have the ability to protect themselves by both immunological and nonimmunological mechanisms. An individual's susceptibility to the impact of environmental agents will determine their adverse effects.This article focuses on air pollution, in particular ozone (O_3), nitrogen dioxide (NO_2), particulate matter (PM) and sulphur dioxide (SO_2). O_3 inhalation first modifies the ciliary cells. O_3 is an extremely strong oxidant, since it increases the permeability of epithelial cells and decreases mucociliary clearance. NO_2 is a less potent and less reactive oxidant pollutant and impairs the function of epithelial cells and alveolar macrophages. PM induces oxidative stress in macrophages and epithelial cells, and increases tumour necrosis factor-beta, interleukin (IL)-6, interferon-gamma, transforming growth factor-p and nuclear factor-kappaB. Diesel exhaust particulate, contained in PM, increases IL-8 production. High concentrations of SO_2 increase the production of reactive oxygen species in the lungs.