Exposurea to Polystyrene Nanoplastics Led to Learning And Memory Deficits in Zebrafish by Inducing Oxidative Damage And Aggravating Brain Aging.

Nanoplastics (NPs) may pass through the blood-brain barrier, giving rise to serious concerns about their potential toxicity to the brain. In this study, the effects of NPs exposure on learning and memory, the primary cognitive functions of the brain, were assessed in zebrafish with classic T-maze exploration tasks. Additionally, to reveal potential affecting mechanisms, the impacts of NPs exposure on brain aging, oxidative damage, energy provision, and the cell cycle were evaluated. Our results demonstrated that NP-exposed zebrafish took significantly longer for their first entry and spent markedly less time in the reward zone in the T-maze task, indicating the occurrence of learning and memory deficits. Moreover, higher levels of aging markers (β-galactosidase and lipofuscin) were detected in the brains of NP-exposed fish. Along with the accumulation of reactive free radicals, NP-exposed zebrafish suffered significant levels of brain oxidative damage. Furthermore, lower levels of ATP and cyclin-dependent kinase 2 and higher levels of p53 were observed in the brains of NP-exposed zebrafish, suggesting that NPs exposure also resulted in a shortage of energy supply and an arrestment of the cell cycle. These findings suggest that NPs exposure may pose a severe threat to brain health, which deserves closer attention. This article is protected by copyright. All rights reserved.