Background The widespread production and disposal of plastics have led to an alarming accumulation of microplastics in the environment, with significant implications for human health. By 2050, 12 billion metric tons of microplastics are expected to be in the environment, a trend exacerbated by the COVID-19 crisis through the increased use of single use plastic gloves and masks. Microplastics have infiltrated various ecosystems worldwide and consequently accumulated in human bodies, posing severe health risks, including the onset and acceleration of neurodegenerative diseases such as Parkinson’s, Alzheimer’s, and multiple sclerosis through mechanisms of neuroinflammation.

Methods This study utilizes a narrative review approach to explore the impact of microplastics on neurodegenerative diseases and the underlying molecular mechanisms. A comprehensive search of relevant literature was conducted using various electronic databases including PubMed, Web of Science, and Google Scholar. The search strategy involved the use of keywords such as "microplastics," "neurodegenerative diseases," "neuroinflammation," "blood-brain barrier," "glial cells," and "Parkinson’s disease," "Alzheimer’s disease," and "multiple sclerosis."

Results The findings indicate that microplastics can infiltrate the CNS through inhalation and direct penetration of the BBB. Detection methods employing engineered nanostructures and gold nanoparticles have been effective in identifying microplastic presence. Moreover, studies using in vitro cultures of glial cells exposed to microplastics showed significant increases in the production of pro-inflammatory cytokines, indicating glial overactivation. In vivo studies in animal models further confirmed these findings, demonstrating that microplastic exposure led to glial cell activation, neuroinflammation, and the acceleration of neurodegenerative disease processes.

Conclusion The findings emphasize the impact of microplastics on CNS health, particularly through the overactivation of glial cells and the resultant neuroinflammation. This study highlights the need for further research into the mechanisms of microplastic-induced neurotoxicity and the development of advanced detection methods and treatments. There is a gap in research regarding the long-term effects of chronic microplastic exposure on the brain and the potential cumulative impact over an individual’s lifespan. Additionally, the study calls for environmental policy changes to reduce microplastic pollution and mitigate its health effects. Given the current trends in plastic production and waste, microplastics are likely to become an even larger issue in the future without swift action.