We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Combined effects of polystyrene micro-/nano-plastics and imidacloprid on Gut–Brain axis and neurotoxicity in juvenile Carassius auratus
Summary
Researchers exposed juvenile crucian carp to polystyrene micro- and nanoplastics combined with the pesticide imidacloprid and found distinct size-dependent toxicity patterns. Nanoplastics primarily targeted the brain, causing blood-brain barrier breakdown and neurotoxic effects linked to behavioral changes, while microplastics caused more severe intestinal damage, with gut microbiome analysis implicating the microbiota-gut-brain axis as a pathway for systemic toxicity.
Polystyrene micro/nanoplastics (PS-MPs/NPs) and the neonicotinoid imidacloprid (IMI) frequently co-occur in freshwater ecosystems, yet their combined toxicity profiles remain distinct and unresolved. Here, we exposed juvenile crucian carp (Carassius auratus) to PS-MPs (5 μm), PS-NPs (60-100 nm), and IMI, alone or in combination, to unravel their interactive mechanisms via a multi-omics approach. Results revealed a clear size-dependent toxicity pattern: while PS-NPs (especially with IMI) preferentially targeted the brain, PS-MPs (with or without IMI) induced the most severe intestinal histological injury, characterized by extensive intestinal fold atrophy and goblet cell depletion. In the brain, co-exposure to PS-NPs and IMI elicited potentiated neurotoxicity, manifesting as blood-brain barrier (BBB) breakdown, neuroinflammation, and a specific disruption of the glutamate-glutamine-γ-aminobutyric acid (Glu-Gln-GABA) metabolic cycle, which coincided with hyperactive and asocial behaviors. Microbiome analysis highlighted distinct dysbiotic signatures. Integrated network analyses further linked these gut microbial shifts to central neurochemical imbalances, implicating the microbiota-gut-brain axis as a potential pathway involved in systemic toxicity. In summary, this study differentiated between gastrointestinal damage caused by MPs and systemic combined toxicity caused by the penetration of NPs and IMI across biological barriers. It emphasizes the importance of size-specific assessment in understanding the complex risks of combined exposure to plastics and pesticides, providing insights for pollution management in agricultural hotspots.