When young and old rodents consumed microscopic plastic fragments in their water over a period of three weeks, researchers at the University of Rhode Island discovered that traces of pollutants had accumulated in every organ of the small mammals, including the brain, as reported by news.ro.

In addition, the existence of these microplastics was linked to behavioral alterations resembling dementia in humans, alongside changes in immune markers within the liver and brain.

"For us, this was striking. There weren't large doses of microplastics, but in just a short period of time, we observed these changes", explained neuroscientist Jaime Ross.

The complete life cycle of these microplastics within the body is still not very well comprehended, which is why the researchers sought to investigate what occurs as the body undergoes aging: "Is the body more vulnerable to systemic inflammation caused by these microplastics as it ages? Can the human body eliminate them as effectively? Do human cells exhibit distinct responses to these toxins?".

It's possible that the results may not directly translate to humans, but studies involving animal models like these represent a crucial first step in clinical research.

Recently, scientists have discovered that microplastics hide in the human intestine, circulate in our blood, accumulate deep in the lungs and infiltrate up to the placenta.

In 2021, toxicologists warned that future studies urgently need to address the impact of these pollutants on human health, especially since exposure is now nearly impossible to avoid.

In recent experiments, both young and old mice were given water treated with fluorescent polystyrene microplastics.

Additionally, plain water was provided to some of the mice as a control group.

Over the course of the three-week study, the behavior of the mice was regularly assessed through open-field tests that encourage exploratory behavior.

They were also subjected to light-dark tests based on rodents' natural aversion to brightly lit areas.

Compared to the control group, mice that ingested water containing microplastics for a duration of three weeks displayed notable alterations in behavior, with older mice showing more pronounced changes.

At the end of the three weeks, red fluorescent microplastic particles were found in every type of tissue examined by the team: brain, liver, kidneys, gastrointestinal tract, heart, spleen and lungs. Additionally, plastic materials were found in the feces and urine of the mice.

The fact that pollutants were detected outside the digestive system suggests that they undergo systemic circulation.

Their presence in the brain is particularly concerning.

It indicates that these potentially toxic pollutants can cross the immune barrier that separates the central nervous system from the rest of the body's bloodstream, potentially leading to neurocognitive problems.

These findings align with another study earlier this year that discovered microplastics in the brains of mice just two hours after consuming a contaminated meal.

In 2022, a similar study also found that ingested polystyrene microplastics can accumulate in the brains of mice, triggering inflammation and affecting their memory.

However, this study did not identify any behavioral changes in the mice during an open-field test.

Despite the discrepancies in results, the team asserts that it is now evident that polystyrene microplastics can reach the brains of mammals and exert harmful effects after absorption.

In their recent study, they discovered that a protein called GFAP, which supports brain cells, decreased following the ingestion of microplastics.

"A decrease in GFAP has been associated with early stages of neurodegenerative diseases, including mouse models of Alzheimer's disease, as well as depression", Ross explained.

"We were very surprised to see that microplastics could induce altered GFAP signaling".

The team intends to investigate these concerning modifications in future research.

The study was published in the International Journal of Molecular Science.