The research team found that microplastics that had been exposed to the weather for several weeks were more easily absorbed by mouse cells than fresh ones. The results of the research are published in the journal Science Advances.
Scientists at the University of Bayreuth in Germany noted that most studies on the effects of animal ingestion of microplastics involved the use of nearly intact specimens. They noted that this practice was likely to produce inaccurate results. The fact is that weathered microplastics differ markedly from those that remain intact. To find out if this is actually the case, scientists conducted experiments in which mouse cells were exposed to microplastics from different sources.
The work involved collecting water samples from an artificial pond, a marine aquarium and a sterile spring. They immersed microplastics in all water samples for two to four weeks. They then removed the microplastic and exposed it to the mouse cells for three hours. The labeling system allowed researchers to observe which cells are absorbing microplastics and to what extent.
As a result, the scientists found that microplastics exposed to natural sources of water were absorbed 10 times more often than microplastics from sterile water. On closer inspection, it turned out that microplastics that have been exposed to nature are covered with a crust consisting of microorganisms and biomolecules. It served as a kind of “Trojan horse” that forced the mouse cell membranes to swallow them and carry them inside the cell. The researchers also noted that after the microplastics entered the cells, it moved into the circulatory system and tissues of the mouse, which triggered an inflammatory response.