title: Airborne particles of the california central valley alter the lungs of healthy adult rats.
abstract: Epidemiologic studies have shown that airborne particulate matter (PM) with a mass median aerodynamic diameter < 10 microm (PM10) is associated with an increase in respiratory-related disease. However, there is a growing consensus that particles < 2.5 microm (PM2.5), including many in the ultrafine (< 0.1 microm) size range, may elicit greater adverse effects. PM is a complex mixture of organic and inorganic compounds; however, those components or properties responsible for biologic effects on the respiratory system have yet to be determined. During the fall and winter of 2000-2001, healthy adult Sprague-Dawley rats were exposed in six separate experiments to filtered air or combined fine (PM2.5) and ultrafine portions of ambient PM in Fresno, California, enhanced approximately 20-fold above outdoor levels. The intent of these studies was to determine if concentrated fine/ultrafine fractions of PM are cytotoxic and/or proinflammatory in the lungs of healthy adult rats. Exposures were for 4 hr/day for 3 consecutive days. The mean mass concentration of particles ranged from 190 to 847 microg/m3. PM was enriched primarily with ammonium nitrate, organic and elemental carbon, and metals. Viability of cells recovered by bronchoalveolar lavage (BAL) from rats exposed to concentrated PM was significantly decreased during 4 of 6 weeks, compared with rats exposed to filtered air (p< 0.05). Total numbers of BAL cells were increased during 1 week, and neutrophil numbers were increased during 2 weeks. These observations strongly suggest exposure to enhanced concentrations of ambient fine/ultrafine particles in Fresno is associated with mild, but significant, cellular effects in the lungs of healthy adult rats.
authors.affiliation: Center for Health and the Environment, University of California, Davis, California, USA.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Smith
authors.forename: Seongheon
authors.initials: S
authors.lastname: Kim
authors.forename: Julian J
authors.initials: JJ
authors.lastname: Recendez
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Teague
authors.forename: Margaret G
authors.initials: MG
authors.lastname: Ménache
authors.forename: David E
authors.initials: DE
authors.lastname: Grubbs
authors.forename: Constantinos
authors.initials: C
authors.lastname: Sioutas
authors.forename: Kent E
authors.initials: KE
authors.lastname: Pinkerton
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D002140:California; D004781:Environmental Exposure; D008168:Lung / Q000737:chemistry*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000393:Air Pollutants