Polystyrene Microplastics May Disrupt Gut-Brain Communication by Activating Brain Immune Receptors and Damage Memory-Related Brain Connections Through an Immune Signaling Pathway

Polystyrene microplastics (PS-MPs) exhibit size-dependent bioaccumulation and neuroinflammation, with 1 μm particles causing the most significant neuroinflammatory response.

• PS-MPs show enhanced barrier penetration at submicron scales, with 500 nm particles having greater bioaccumulation than larger ones.
• 1 μm PS-MPs induce maximum neuroinflammation despite lower overall distribution compared to 500 nm particles.
• Both sizes of PS-MPs cause disruption of the gut barrier, leading to increased levels of circulating lipopolysaccharides (LPS).
• Translocation of LPS across the compromised blood-brain barrier triggers activation of the TLR4/MyD88/NF-κB pathway.
• This activation results in a rise in pro-inflammatory cytokines, contributing to synaptic lesions in the hippocampus.
• Smaller PS-MPs (≤1 μm) may pose significant risks for neurodegeneration, highlighting the need for further evaluation of chronic exposure effects.

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