Particulate Urban Air Pollution Affects the Functional Morphology of Mouse Placenta1

Abstract

In humans, adverse pregnancy outcomes (low birth weight, prematurity, and intrauterine growth retardation) are associated with exposure to urban air pollution. Experimental data have also shown that such exposure elicits adverse reproductive outcomes. We hypothesized that the effects of urban air pollution on pregnancy outcomes could be related to changes in functional morphology of the placenta. To test this, future dams were exposed during pregestational and gestational periods to filtered or nonfiltered air in exposure chambers. Placentas were collected from near-term pregnancies and prepared for microscopical examination. Fields of view on vertical uniform random tissue slices were analyzed using stereological methods. Volumes of placental compartments were estimated, and the labyrinth was analyzed further in terms of its maternal vascular spaces, fetal capillaries, trophoblast, and exchange surface areas. From these primary data, secondary quantities were derived: vessel calibers (expressed as diameters), trophoblast thickness (arithmetic mean), and total and mass-specific morphometric diffusive conductances for oxygen of the intervascular barrier. Two-way analysis of variance showed that both periods of exposure led to significantly smaller fetal weights. Pregestational exposure to nonfiltered air led to significant increases in fetal capillary surface area and in total and mass-specific conductances. However, the calibers of maternal blood spaces were reduced. Gestational exposure to nonfiltered air was associated with reduced volumes, calibers, and surface areas of maternal blood spaces and with greater fetal capillary surfaces and diffusive conductances. The findings indicate that urban air pollution affects placental functional morphology. Fetal weights are compromised despite attempts to improve diffusive transport across the placenta.

Impact of short-term preconceptional exposure to particulate air pollution on treatment outcome in couples undergoing in vitro fertilization and embryo transfer (IVF/ET)

“…Veras et al [33] showed that ambient levels of PM may impair reproductive health by affecting the maternal side of the placental interface between the mother and the fetus. Preand/or gestational exposure of female mice to non-filtered urban air led to reduced volumes, diameters, and surface areas of maternal blood spaces and significant increases in fetal capillary surface area and the total and mass-specific morphometric diffusive conductances for oxygen of the intervascular barrier.…”

DOHaD

“…D'autres hypothèses, comme celle d'un effet des polluants atmosphériques sur la circulation foeto-placentaire sont explorées. Chez le rongeur, des travaux ont montré que l'exposition prénatale aux particules issues du trafic routier (les animaux étant exposés directement au trafic), affecte la fonction placentaire [51]. Chez l'homme, l'exposition aux particules PM 10 et au dioxyde d'azote a été associée à des variations du poids du placenta ou du ratio foeto-placentaire [52].…”

Pre and Post-Natal Exposure to Air Pollution is Public Health Problem

“…The pregnancy period is critical because mother's exposure to air pollutants could affect the fetal development of humans and animals.Studies in animals and humans had demonstrated the association between the mother's exposure to air pollutants, neonatal mortality and birth defects [1][2][3][4]. Veras et al [3] demonstrated an increase in transplacental diffusion of substances in female mouse which were exposed to air pollution at ambient level during the pre-pregnancy and pregnancy periods.…”

“…Veras et al [3] demonstrated an increase in transplacental diffusion of substances in female mouse which were exposed to air pollution at ambient level during the pre-pregnancy and pregnancy periods. In 2009 [4], the same researchers showed that females which inhaled PM (particulate matter) at ambient level presented a decrease in the number of cicles, of folicules and embryo implantation as well as lower weight of puppies.…”