Transmission electron microscopy findings in the respiratory epithelium of guinea pigs exposed to the polluted air of southwest Mexico City

We evaluated the nature and the extent of the damage to the respiratory epithelium of guinea pigs after a 4-month exposure to the mixture of air pollutants in southwest Mexico City. Guinea pigs were placed outdoors on the roof of our facility, 8 hours daily, from February to May 1995. At the same ti...

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Published inJournal of environmental pathology, toxicology and oncology Vol. 18; no. 4; p. 323
Main Authors Villegas-Castrejon, H, Villalba-Caloca, J, Meneses-Flores, M, Haselbarth-Lopez, M M, Flores-Rivera, E, Perez-Neria, J
Format Journal Article
LanguageEnglish
Published United States 1999
Subjects
Air Pollutants - adverse effects
Air Pollutants - analysis
Animals
Body Weight - drug effects
Cilia - drug effects
Cilia - ultrastructure
Environmental Monitoring
Guinea Pigs
Inhalation Exposure - adverse effects
Macrophages, Alveolar - drug effects
Macrophages, Alveolar - ultrastructure
Male
Mexico
Microscopy, Electron - methods
Ozone - analysis
Respiratory Mucosa - drug effects
Respiratory Mucosa - ultrastructure
Single-Blind Method
Mexico
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Summary:We evaluated the nature and the extent of the damage to the respiratory epithelium of guinea pigs after a 4-month exposure to the mixture of air pollutants in southwest Mexico City. Guinea pigs were placed outdoors on the roof of our facility, 8 hours daily, from February to May 1995. At the same time, control guinea pigs were kept indoors breathing filtered air. Air pollutants, temperature, and humidity data were obtained from the nearest station of the Environmental Monitoring Net. The airways and lung parenchyma were analyzed after 120 days using transmission electron microscopy (TEM). During the 4-month exposure period, ozone (O3) exceeded the norm during 511 hours, and suspended particles less than 10 microm in diameter (PM10) during 52 hours. Both pollutants reached peak levels of more than twice the norm. TEM revealed no important abnormalities in the control group. In the exposed group, there was loss of cilia, detachment of epithelial cells, and eosinophil and macrophage migration toward alveolar spaces through type I pneumocytes with destruction of their basal membranes. In six guinea pigs in the exposed group, we noted bacteria along the airways, with associated inflammatory response. We explain the colonization of the respiratory epithelium by bacteria as the result of the impairment on the defense mechanism caused by the exposure to environmental O3 and PM10.
ISSN:0731-8898