AIRBORNE PARTICULATE MATTER MODULATES THE PRODUCTION OF REACTIVE OXYGEN SPECIES IN HUMAN POLYMORPHONUCLEAR GRANULOCYTES

Causal relationships between airborne particles (especially particulat e matter < 10 mu m in diameter) and increases in prevalences and sympt oms of respiratory diseases have been postulated in many epidemiologic studies. Polymorphonuclear leukocytes (PMN) in the nasal or bronchial epithelium can be exposed to particulate matter (PM) and may upon exp osure produce reactive oxygen species (ROS). Release of ROS can result in cellular and tissue damage and initiate or exacerbate inflammation . To elucidate the effect of PM on inflammatory reactions, we exposed human PMN to PM extracts. PM were collected with high volume samplers in two cities, Dusseldorf and Duisburg, in Germany and reflect sites w ith high traffic and industrial emissions respectively. The collected particles were extracted using water and then dichloromethane, resulti ng in an aqueous and an organic extract. The production of ROS was det ermined using luminol-enhanced chemiluminescence (LCL) of resting and zymosan-stimulated PMN. The present study shows that extracts of PM al one significantly stimulated the production and release of ROS in rest ing PMN. The effects of the PM extracts were inhibited by superoxide d ismutase (SOD), catalase and sodium azide (NaN3). Zymosan-induced LCL was, however, diminished by coincubation with PM extracts. The chemica l composition is important when considering the effects of particles. Our study shows that only organic substances adsorbed to particles sti mulate LCL. SOZ-induced LCL is inhibited by both types of extracts, bu t aqueous extracts have a stronger inhibitory effect. II is at present unclear which substances are responsible for these effects. (C) 1997 Elsevier Science Ireland Ltd.