Small plastic particles in the lungs of pregnant rats quickly pass to the heart, brain and other organs of their fetuses, research shows. It is the first study in a living mammal to show that the placenta does not block such particles.
The experiments also showed that rat fetuses exposed to the particles gained significantly in weight towards the end of gestation. The research follows the revelation in December of tiny plastic particles in human placentas, which scientists described as “a matter of great concern.” Previous laboratory research on human placentas donated by mothers after birth has also shown Styrofoam beads can cross the placental barrier.
Microplastic pollution has reached all parts of the planet, from the top of Mount Everest to the deepest oceans, and it is already known that people consume the small particles through food and water, and breathe them.
The health impact of the tiny plastic particles in the body is still unknown. But scientists say there is an urgent need to assess the problem, particularly for developing fetuses and babies, as plastics can contain chemicals that could cause long-term damage.
Professor Phoebe Stapleton of Rutgers led the research in rats and said: “We find the plastic nanoparticles everywhere we look: in maternal tissues, in the placenta and in fetal tissues. We find them in the heart, brain, lungs, liver and kidneys of the fetus ”.
Dunzhu Li, from Trinity College Dublin (TCD) in Ireland, who is not part of the study team, said: “This study is very important because it shows the potential to transfer [plastic particles] In mammalian pregnancy, perhaps it is also happening from the beginning of human life. The particles were found almost everywhere in the fetus and can also cross the blood-brain barrier; it’s very shocking. “
Professor John Boland, also from TCD, said: “However, it is important not to over-interpret these results. The nanoparticles used are almost spherical in shape, whereas real microplastics are irregular, flaky objects. The shape matters, as it dictates how the particles interact with their environment. “In October, Li, Boland and their colleagues showed that babies fed formula in plastic bottles ingest millions of particles a day.
The rat study was published in the journal Particle and Fiber Toxicology and it involved placing nanoparticles in the trachea of the animals. Stapleton said the amount of particles used was estimated to be equivalent to 60% of the amount a human mother would be exposed to in one day, although Li’s opinion was that this estimate was too high.
The 20-nanometer beads used were made from polystyrene, which is one of the five most important plastics found in the environment, Stapleton said. They were labeled with a fluorescent chemical to allow their identification. A separate experiment showed that the nanoparticles crossed the placenta approximately 90 minutes after the mothers were exposed.
Twenty-four hours after exposure, the weight of the fetuses was on average 7% less than in control animals, and the weight of the placenta was 8% less. Weight loss was also observed in other experiments with titanium dioxide particles. The rats were exposed to the plastic nanoparticles on day 19 of gestation, two days before the usual time for birth and when the fetus is gaining the most weight.
“Our working theory is that something in the maternal vasculature changes, so you get a reduction in blood flow, which in turn leads to a reduction in the supply of nutrients and oxygen,” Stapleton said.
She said more research is needed: “This study answers some questions and opens up other questions. We now know that the particles can pass through the fetal compartment, but we don’t know if they are lodged there or if the body just separates them, so there is no additional toxicity. “
Stapleton said that the nanoparticles used in his research are a million times smaller than the microplastics found in human placentas and are therefore currently much more difficult to identify in human studies. “But we know that nanoparticles are more toxic than microparticles of the same chemical, as the smaller particles penetrate deeper into the lungs.”
The next step for the researchers is to place the rats in an “inhalation chamber,” where the particles can be inhaled, rather than placed in the windpipe. This also allows for chronic exposure assessment, where lower doses are given over longer periods, rather than a large dose.
Previous research in rats has shown that silver and carbon nanoparticles pass from mother to fetus and damage health. Inhumans, inhaled gold nanoparticles they were later found in the blood and urine of volunteers and were still present after three months.
George is Digismak’s reported cum editor with 13 years of experience in Journalism