Effect of Early-Life Exposure of Polystyrene Microplastics on Behavior and DNA Methylation in Later Life Stage of Zebrafish.

Microplastic contamination has received increasing attention in recent years, and concern regarding the toxicity of microplastics to the environment and humans has increased. In this study, we investigated the neurodevelopmental toxicity of polystyrene microplastics (PSMPs) in the zebrafish Danio rerio under different exposure scenarios. Zebrafish were exposed to PSMPs during embryonic stage and then allowed the fish to recover. The neurodevelopmental toxic responses were investigated using fish behavior and behavior-related gene expression. Early-life exposure to PSMPs did not alter fish behavior at the early stage; however, it led to hyperactivity later life stage. Generally, oxidative stress (i.e., sod2 and nrf2a)- and nervous system (i.e., slc6a4b, npy, and nrbf2)-related gene expression increased in all PSMPs-exposed fish. DNA hypomethylation was observed in fish challenged for a second time using the same PSMPs. Taken together, the current results imply that PSMPs have neurodevelopmental toxic potential when introduced early in life.