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Gut microbiota-GABA axis dysregulation underlies polystyrene microplastic (PS-MP) neurotoxicity in rainbow trout: a role for oxidative stress and blood-brain barrier disruption.

NPJ biofilms and microbiomes 2026

Summary

Researchers exposed rainbow trout to polystyrene microplastics for 14 days and found that particles accumulating in the gut and brain caused blood-brain barrier damage, gut dysbiosis, and suppressed GABA synthesis, establishing the gut microbiota-GABA signaling axis as a key pathway through which microplastics induce neurocognitive impairment in a commercially important aquaculture species.

Polymers
Body Systems

Microplastics (MPs) threaten aquatic ecosystems and pose potential risks to organismal health through bioaccumulation in aquatic species. This study reveals that 14-day exposure to 5 μm polystyrene microplastics (PS-MPs) (500 μg/L) induces neurocognitive impairment in rainbow trout (Oncorhynchus mykiss), a globally consumed aquaculture species. MPs accumulated in brain and gut tissues, causing blood-brain barrier structural alterations, intestinal mucosal damage, and oxidative stress. Multi-omics analysis revealed associations between gut microbiota dysbiosis (reduced Ralstonia, increased Acinetobacter) to suppressed neuroactive pathways, particularly GABA synthesis and transport. Downregulation of monocarboxylate transporters (mct1/2) and GABA-related enzymes (GAD1/2) disrupted gut-to-brain GABA homeostasis, neurobehavioral deficits. These findings establish the gut microbiota-GABA axis as a critical mediator of MPs neurotoxicity, highlighting risks to seafood safety and necessitating urgent regulation of microplastic contamination in aquatic food chains.

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