Microplastics Infiltrate the Developing Brain and Trigger Lasting Neurological Damage

Micro- and nanoplastics (MNPs) have become inescapable contaminants in the modern environment, detected in food, drinking water, and even human blood and breast milk. Their ability to cross biological barriers — including the placenta and the blood-brain barrier — raises urgent questions about whether early-life exposure shapes long-term neurological health. This systematic review, conducted following PRISMA guidelines and registered with PROSPERO, synthesizes findings from 20 experimental rodent studies to characterize the neurotoxic effects of MNP exposure across critical developmental windows.

Researchers searched four major databases without date restrictions, applying a PECO framework that focused on mammalian in vivo models exposed to MNPs during gestation, lactation, childhood, or adolescence. Particles studied included polystyrene, polypropylene, polyethylene, and polyvinyl chloride, delivered primarily by oral routes. Study reliability was appraised using ToxRTool, and findings were narratively synthesized by exposure window due to methodological heterogeneity.

Across prenatal, postnatal, and combined exposure windows, convergent findings emerged at multiple biological levels. Oxidative stress and mitochondrial dysfunction were consistently observed, alongside neuroinflammation characterized by microglial and astrocytic activation. Structural disruptions included impaired neurogenesis, abnormal myelination, and synaptic and dendritic abnormalities. Neurochemically, GABAergic and glutamatergic imbalances were frequent, with context-dependent dopaminergic changes. Behaviorally, exposed animals showed impaired learning and memory, heightened anxiety, altered sociability, and repetitive or stereotyped behaviors. Several studies implicated the gut-brain axis, with MNPs inducing intestinal barrier disruption, dysbiosis, and systemic inflammation that amplified central nervous system effects.

For longevity-minded readers, the implications extend beyond childhood: neuroinflammation and synaptic dysfunction are core mechanisms in age-related cognitive decline, and early neurotoxic insults may lower the threshold for later neurodegeneration. Reducing plastic exposure could be a meaningful environmental lever for preserving long-term brain health.

Important caveats apply. Only 20 studies met inclusion criteria, all in rodents, and exposure doses and paradigms varied considerably. Sex-stratified analyses were largely absent, limiting understanding of differential vulnerability. Translation to human health outcomes remains speculative until environmentally relevant dosing and longitudinal human studies are conducted.