title: Acute pulmonary toxicity of urban particulate matter and ozone.
abstract: We have investigated the acute lung toxicity of urban particulate matter in interaction with ozone. Rats were exposed for 4 hours to clean air, ozone (0.8 ppm), the urban dust EHC-93 (5 mg/m3 or 50 mg/m3), or ozone in combination with urban dust. The animals were returned to clean air for 32 hours and then injected (intraperitoneally) with [3H]thymidine to label proliferating cells and killed after 90 minutes. The lungs were fixed by inflation, embedded in glycol methacrylate, and processed for light microscopy autoradiography. Cell labeling was low in bronchioles (0.14 +/- 0.04%) and parenchyma (0.13 +/- 0.02%) of air control animals. Inhalation of EHC-93 alone did not induce cell labeling. Ozone alone increased (P < 0.05) cell labeling (bronchioles, 0.42 +/- 0.16%; parenchyma, 0.57 +/- 0.21%), in line with an acute reparative cell proliferation. The effects of ozone were clearly potentiated by co-exposure with either the low (3.31 +/- 0.31%; 0.99 +/- 0.18%) or the high (4.45 +/- 0.51%; 1.47 +/- 0.18%) concentrations of urban dust (ozone X EHC-93, P < 0.05). Cellular changes were most notable in the epithelia of terminal bronchioles and alveolar ducts and did not distribute to the distal parenchyma. Enhanced DNA synthesis indicates that particulate matter from ambient air can exacerbate epithelial lesions in the lungs. This may extend beyond air pollutant interactions, such as to effects of inhaled particles in the lungs of compromised individuals.
authors.affiliation: Environmental Health Directorate, Health Canada, Ottawa, Ontario, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Vincent
authors.forename: S G
authors.initials: SG
authors.lastname: Bjarnason
authors.forename: I Y
authors.initials: IY
authors.lastname: Adamson
authors.forename: C
authors.initials: C
authors.lastname: Hedgecock
authors.forename: P
authors.initials: P
authors.lastname: Kumarathasan
authors.forename: J
authors.initials: J
authors.lastname: Guénette
authors.forename: M
authors.initials: M
authors.lastname: Potvin
authors.forename: P
authors.initials: P
authors.lastname: Goegan
authors.forename: L
authors.initials: L
authors.lastname: Bouthillier
mesh_terms: D000208:Acute Disease; D000280:Administration, Inhalation; D000393:Air Pollutants / Q000737:chemistry / Q000633:toxicity*; D000818:Animals; D001345:Autoradiography; D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D004261:DNA Replication / Q000187:drug effects; D004781:Environmental Exposure; D008168:Lung / Q000187:drug effects / Q000473:pathology; D008171:Lung Diseases / Q000139:chemically induced / Q000473:pathology*; D008297:Male; D010126:Ozone / Q000633:toxicity*; D051381:Rats; D011916:Rats, Inbred F344; D014504:Urban Health; D010130:p-Aminohippuric Acid / Q000032:analysis
chemical_list: D000393:Air Pollutants; D010126:Ozone; D004247:DNA; D010130:p-Aminohippuric Acid