How do microplastics impair brain function?

29 Jan 2025

Written by Emma Hall (Contributing Editor)

Microplastics can impair brain function by trapping immune cells and blocking blood vessels, raising concerns about their long-term impact on human health.

Microplastics – tiny particles formed from degraded plastics – are a serious environmental and health concern, and their presence in the environment is rapidly increasing. A recent study published in Science Advances has highlighted how microplastics can disrupt brain function in mice by trapping immune cells in cerebral blood vessels, obstructing blood flow and leading to neurological abnormalities in mice. Using high-depth imaging, blood sample processing and flow cytometry, researchers revealed a newly discovered mechanism by which microplastics can interfere with tissue function, raising questions about the potential risks of microplastics in the human bloodstream.

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I’m sure you’re well aware of the threat of microplastic pollution on human health. But how exactly do microplastics enter our bodies? The answer is pretty much through everything: food, water, air and even medical devices, allowing them to cross biological barriers and interact with numerous physiological processes in our bodies. And the outcome of this? Although previous studies have linked nanoscale plastics to inflammation and neurological disorders, the effects of larger, micron-sized particles and how exactly they can cause functional irregularities in the brain remain unclear.

The team, led by researchers from the Chinese Research Academy of Environmental Sciences (Beijing, China), has now revealed a specific mechanism behind how microplastics interfere with tissue function.

In the study, researchers injected fluorescent microplastics of three sizes — 5 µm (micron-sized), 2 µm and 80 nm (nanoscale) — into mice to simulate human exposure levels. Using advanced imaging techniques to track real-time microplastic movements and flow cytometry analysis to identify different immune cells from blood samples, they observed that immune cells engulfing microplastics (MPL-cells) became trapped in brain capillaries, obstructing blood flow within just 30 minutes. Larger microplastic particles caused more prolonged blockages.

Behavioral tests revealed that exposed mice exhibited reduced movement, impaired memory and weakened motor coordination. Although these impairments improved within 4 weeks, some vascular obstructions persisted. Flow cytometry analysis demonstrated that microplastics altered both immune cell morphology and adhesiveness following phagocytosis, exacerbating blockages.

These findings emphasize the potential health risks of microplastics, particularly their impact on brain function through vascular disruptions. While findings in mice cannot yet be directly applied to humans, they highlight the need for further research on long-term microplastic exposure and its effects on vulnerable populations. The researchers also stress that it is still unclear which cellular signaling pathways and cell surface receptors are altered by microplastic phagocytosis, and that this should be investigated further. Nevertheless, the research offers an important foundation for understanding the potential health risks posed by microplastic pollution and is an important step forward in safeguarding public health.