An animal study concludes that in utero exposure to air pollution can have consequences on the offspring, over two generations.
Chronic exposure to diesel engine exhaust has serious consequences for the unborn child, spanning several generations. A study carried out in rabbits by researchers from the National Institute for Agronomic Research (INRA) and published in Particle and Fiber Toxicology reveals, in fact, that this pollution causes abnormal growth and metabolism in the fetus over 2 generations.
Of previous work led by an Inserm team from Grenoble have shown that pregnant women exposed to air pollution, especially fine particles, are more likely to give birth to low birth weight babies. In adulthood, these children suffer more than others from cardiovascular disorders. Worrisome conclusions as pollution peaks multiply.
Although these epidemiological studies suggested a link between pollution and growth retardation in the fetus, they could not explain how fine particles affect embryonic and fetal development. This is precisely the objective of the research project “Effects of Atmospheric Pollution on Placental Function and Post-natal Development” coordinated by INRA.
Growth retardation
The researchers studied the effect of fine particles and harmful gases, such as carbon monoxide and nitrogen oxides, in pregnant rabbits, a model much closer to humans than mice. The guinea pigs inhaled “filtered diesel engine exhaust (containing only ultrafine particles or nanoparticles, as in diesel car engines) at levels close to the daily exposure of the population during a pollution peak. to fine particles in major European cities, ”explains INRA.
Halfway through gestation, the ultrasound revealed a sharp decrease in the blood supply to the placenta, reducing the supply of nutrients to the fetus as well as signs of retarded fetal growth. Anomalies confirmed at birth: the young rabbits presented smaller heads than normal and a reduced waist size.
Nanoparticles cross the placental barrier
In addition, the analysis of the placenta by electron microscopy shows the presence of nanoparticles originating from the gases inhaled by the rabbits. These have also been found in the blood of the fetus. This is the first time that scientists have shown that inhaled diesel nanoparticles are able to cross the placental barrier and reach the fetus.
Further work with rabbits born to exposed mothers and mated with males who have not been exposed to this pollution suggests that the effects persist for at least 2 generations. The young rabbits did not exhibit growth retardation but abnormalities in the exchange of lipids between the mother and the fetus were observed by the researchers. This would show, according to them, the effect of exposure to pollution in the 2nd generation.
For scientists, this animal work suggests that pregnant women should take precautions during pollution peaks. They would be as vulnerable as children or the elderly.
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