The neurotoxic threat of micro- and nanoplastics: evidence from In Vitro and In Vivo models

Micro- and nanoplastics (MPs/NPs), ubiquitous contaminants in ecosystems and food chains, have emerged as a significant concern due to their potential neurotoxic effects on human health. Here, we conducted a systematic review of the existing literature, which included 26 studies providing evidence from cellular and animal studies on the risks posed by MPs/NPs to the nervous system. In vitro studies reveal that MPs/NPs can disrupt the integrity of the blood-brain barrier, penetrate neurons and glial cells, impair cell membrane integrity, and induce cytotoxic effects. These plastic particles trigger oxidative stress, inflammation, and mitochondrial dysfunction, alter signaling pathways, and disrupt neuronal communication, potentially leading to neurological dysfunction, cognitive deficits, and neurodegenerative disorders like Alzheimer's and Parkinson's diseases. Animal models corroborate these findings, demonstrating behavioural changes, memory impairment and neurotransmitter imbalances following exposure to MPs/NPs. Although the evidence in humans is limited, the growing body of hazard data underlines the potential risks associated with chronic exposure and accumulation of MPs/NPs in the nervous system. This highlights the urgent need for further research to elucidate the mechanisms of neurotoxicity, as well as stringent regulatory measures to restrain plastic pollution and safeguard neurological health.