Microplastic-induced neurotoxicity in Zebrafish: Current evidence and underlying mechanisms

It has been observed that researchers from the biological field are emphasising more on Microplastics (MPs), a rising contaminant, which is documented for brain toxicity in brain physiology, raising our interest to review the impact of MPs on zebrafish (Danio rerio) neurotoxicity. Several pathways of neurotoxic effects of MPs on zebrafish are consolidated in this review. In contrast, MPs, which can accumulate in the zebrafish brain, exhibit unique neurotoxic mechanisms, including physical damage to neuronal structures, interference with synaptic transmission, and the leaching of chemical additives. MPs may exert further neurotoxic effects. Emerging evidence suggests that MPs can result in altered behaviour, including anxiety-like responses and impaired social interactions, and stimulate varied neurotoxic pathways. Moreover, decreased activity of Acetylcholinesterase (AChE) in fish exposed to MPs highlights its link to neurotoxic outcomes. Further, reactive oxygen species (ROS) inflammation and an increase in apoptosis occur in the brain of zebrafish due to MPs accumulation. Our review underscores the pressing need for understanding the implications of this environmental contaminant on the brain physiology of zebrafish at the molecular level, especially considering the possible effects it could have on human health via the food chain.