title: Alveolar macrophage interaction with air pollution particulates.
abstract: We applied flow cytometric analysis to characterize the in vitro response of alveolar macrophages (AM) to air pollution particulates. Normal hamster AM were incubated with varying concentrations of residual oil fly ash (ROFA) or concentrated ambient air particulates (CAP). We found a dose-dependent increase in AM-associated right angle light scatter (RAS) after uptake of ROFA (e.g., mean channel number 149.4 +/- 6.5, 102.5 +/- 4.1, 75.8 +/- 3.5, and 61.0 +/- 4.6 at 200, 100, 50, and 25 mg/ml, respectively) or CAP. A role for scavenger-type receptors (SR) in AM uptake of components of ROFA and CAP was identified by marked inhibition of RAS increases in AM pretreated with the specific SR inhibitor polyinosinic acid. We combined measurement of particle uptake (RAS) with flow cytometric analysis of intracellular oxidation of dichlorofluorescin. Both ROFA and CAP caused a dose-related intracellular oxidant stress within AM, comparable to that seen with phorbol myristate acetate (PMA) (e.g., fold increase over control, 6.6 +/- 0.4, 3.6 +/- 0.4, 4.6 +/- 0.5, 200 mg/ml ROFA, 100 mg/ml ROFA, and 10(-7) M PMA, respectively). We conclude that flow cytometry of RAS increases provides a useful relative measurement of AM uptake of complex particulates within ROFA and CAP. Both ROFA and CAP cause substantial intracellular oxidant stress within AM, which may contribute to subsequent cell activation and production of proinflammatory mediators.
authors.affiliation: Dept. of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Goldsmith
authors.forename: C
authors.initials: C
authors.lastname: Frevert
authors.forename: A
authors.initials: A
authors.lastname: Imrich
authors.forename: C
authors.initials: C
authors.lastname: Sioutas
authors.forename: L
authors.initials: L
authors.lastname: Kobzik
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D002244:Carbon / Q000633:toxicity*; D003031:Coal / Q000633:toxicity*; D060729:Coal Ash; D006224:Cricetinae; D005434:Flow Cytometry; D016166:Free Radical Scavengers / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000187:drug effects*; D008647:Mesocricetus; D016877:Oxidants / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D052638:Particulate Matter; D010587:Phagocytosis / Q000187:drug effects
chemical_list: D000393:Air Pollutants; D003031:Coal; D060729:Coal Ash; D016166:Free Radical Scavengers; D016877:Oxidants; D052638:Particulate Matter; D002244:Carbon