Stage-specific effects of nanoplastic exposure on neurodevelopment and offspring behavior

With the continuous increase in plastic production, nanoplastics (NPs) derived from degrading plastic products have emerged as a critical environmental pollutant. NPs have been found in the human placenta and breast milk; however, the potential effects of NP exposure in various developmental stages remain elusive and require further investigation. We aimed to investigate the effects of maternal NP exposure on neurodevelopment during the embryonic and postnatal periods. First, mice exposed to 100 μg/mL NPs in the embryonic or postnatal stage demonstrated reduced problem-solving proficiency and learning memory deficiencies in adulthood. Notably, embryonic NP exposure resulted in anxiety-like behavior and impaired recognition memory, whereas postnatal exposure did not have significant effects. NP exposure in the embryonic stage resulted in increased neural progenitor proliferation and thus, expansion of the neural progenitor pool in the embryonic brain, and induced cell apoptosis in the early postnatal brain. NP exposure perturbed neurogenic gene expression and overactivated AKT-GSK3β signaling in the embryonic brain. The disruption of neurogenesis by 100 μg/mL NPs was confirmed using in vitro mouse neural stem cells. Our findings reveal the potential risks posed by NP exposure during early development and the neurodevelopmental consequences of NP exposure in early life.