Effects of Nanoplastics on Behavior and Energy Metabolism of Zebrafish Larvae

Microplastics and nanoplastics have become important factors threatening the health of aquatic organisms. In this study, zebrafish (Danio rerio) larvae were used as model organisms to investigate the short-term effects of nanoplastic exposure on the behavior and metabolism of juvenile fish. The larvae were exposed to environments containing fluorescent polystyrene nanoplastics (PSNP), 25 nm and 80 nm in diameter, respectively, to detect nanoplastic accumulation and assess their effects on zebrafish larval behavior and metabolism. The results showed that after 9 hours of treatment, 25 nm PSNP specifically accumulated in the brain tissues of zebrafish while 80 nm PSNP tended to accumulate on the surface of zebrafish larvae. The 25 nm PSNP significantly inhibited the touch-evoked reponse of zebrafish larvae; and significantly reduced the contents of glucose thus inhibited glycolysis and the tricarboxylic acid cycle metabolic pathways. Additionally, 25 nm PSNP significantly reduced the level of adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH). These results indicated that bioaccumulation of nanoplastics is related to their particle size, and nanoplastics significantly inhibit the energy metabolism of zebrafish larvae. Our findings provided important insights for assessing the impact of nanoplastic pollutant on the behavior and metabolism of juvenile fish.