Inhalation of Nebulized Diesel Particulate Matter: A Safety Trial in Healthy Humans

摘要

Diesel particulate matter (DPM) has adverse health effects. Examining the underlying pathophysiological mechanisms would befacilitated by the introduction of an exposure method that is safe, portable, and cost-effective. The purpose of this study was toestablish a novel method to study DPM exposure via nebulization and an inhalation dose that was safe, yet capable of elicitingan inflammatory response. Ten participants enrolled in this nonblinded, nonrandomized study. Subjects inhaled nebulized 0.9%saline and increasing doses of DPM suspended in 0.9% saline (75, 150, and 300 g) in a sequential manner. FEV1 was measuredrepeatedly during the first 2 h after exposure and blood, oximetry, sputum, and heart rate were taken before, 2 h, and 24 h afterinhalation challenge. DPM inhalation was well-tolerated at all doses. A decrease in FEV1 was observed after each inhalationchallenge (including saline). Inhalation of 300 g DPM produced a significantly different FEV1 response curve. An increase inparticle inclusion-positive sputum macrophages for all DPM doses confirmed that the nebulized particles were reaching the lowerairways. SerumGM-CSF was elevated after exposures to 150 and 300 gDPM.No other inflammatory changes were detected.DPMinhalation via nebulizer is a safe method of delivering low doses of DPMs in healthy people.