Mauad T, Rivero DH, Carvalho de Oliveira R, Lichtenfels AJ, Guimaraes ET, de Andre PA, Kasahara DI, Bueno HM, Saldiva PH
Chronic Exposure to Ambient Levels of Urban Particles Affects Mouse Lung Development. [JOURNAL ARTICLE]
Am J Respir Crit Care Med 2008 Jul 2.
RATIONALE: Chronic exposure to air pollution has been associated with adverse effects on children's lung growth.
OBJECTIVES: We analyzed the effects of chronic exposure to urban levels of particulate matter (PM) on selected phases of mouse lung development.
METHODS: The exposure occurred in two open-top chambers (filtered and non-filtered) placed 20m from a street with heavy traffic in Sao Paulo, 24 hours/day for eight months. There was a significant reduction of the levels of PM2.5 inside the filtered chamber (filtered=2.9+/-3.0 microg/m(3), non-filtered=16.8+/-8.3 microg/m(3); p=0.001). At this exposure site, vehicular sources are the major components of PM2.5 (PM</=2.5Km). Exposure of the parental generation in the two chambers occurred from the 10th to the 120th days of life. After mating and birth of offspring, a cross-over of mothers and pups occurred within the chambers, resulting in four groups of pups: non-exposed, prenatal, postnatal and pre+postnatal. Offspring were euthanized at the age of 15 (n=42) and 90 (n=35) days; lungs were analyzed by morphometry for surface to volume ratio (as an estimator of alveolization). Pressure-volume curves were performed in the older groups, using a 20ml plethysmograph.
RESULTS: Mice exposed to PM2.5 pre+postnatally presented a smaller surface to volume ratio when compared to non-exposed animals (p=0.036). The pre+postnatal group presented reduced inspiratory and expiratory volumes at higher levels of transpulmonary pressure (p=0.001). There were no differences among prenatal and postnatal exposure and non-exposed animals.
CONCLUSIONS: Our data provide anatomical and functional support to the concept that chronic exposure to urban PM affects lung growth.
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