Plastic pollution isn't just a menace to the environment anymore, but its damage now extends to several aspects of human health. The tiny particles of plastic that are not even visible to the human eye make their way into the body through food, inhalation, and skin contact.

No wonder microplastics have been detected throughout the human body, be it blood, saliva, liver, kidneys, and placenta. A study published by JAMA Network identifies microplastics (MPs), particularly polypropylene and nylon, in the olfactory bulb (OB), suggesting that inhalation may be a key route for environmental pollutants to enter the brain. The presence of microplastics in human brain tissue has been confirmed by previous studies and it has also been suggested that the brain may be particularly susceptible to microplastic accumulation compared to other organs.

Now a new study, published in the Journal of Science Advances, sheds light on how these microplastics travel to the brain and lead to life-threatening blood flow blockages.

Led by a team from the Chinese Research Academy of Environmental Sciences in Beijing, the study tracked the movement of microplastics in blood vessels of mouse brains in real-time, in a first-of-its-kind experiment.

How to study was carried out
The researchers used high-resolution laser-based imaging techniques and found microplastic-laden immune cells getting embedded inside the blood vessels in the brain's cortex area.

"Our data reveal a mechanism by which microplastics disrupt tissue function indirectly through regulation of cell obstruction and interference with local blood circulation, rather than direct tissue penetration," write the researchers in their published paper.

"This revelation offers a lens through which to comprehend the toxicological implications of microplastics that invade the bloodstream."

How these brain blockages impacted the behavior of mice

The scientists involved in the experiment noted some similarities between brain blockages in the mouse and blood clots, and also observed how it affected the behavior of the mouse.

It was observed that mice with microplastics in their blood had deteriorated movement, memory, and coordination tests compared to those who didn't have the plastic in their brain, indicating slowed down cognitive health.

However, when these microplastic blockages were removed, the cognitive behavior in the mice resumed to normal which led the researchers to understand the blockages could be linked to neurological problems like depression and anxiety, as well as an increased risk of strokes and cardiovascular disease.

"These findings indicate that mice display multifaceted abnormalities in neurobehavioral regulation, resembling depressive states associated with disrupted cerebral blood flow," write the researchers.

These insights will also help scientists understand how microplastics may be impacting human brains. Although there is a significant difference in terms of immune systems and blood vessel sizes, mice are biologically similar to humans.

"The potential long-term effects of microplastics on neurological disorders such as depression and cardiovascular health are concerning," said the scientists.