Current Insights into Plausible Mechanisms of Chromium (VI) Neurotoxicity in the Brain and Future Perspectives

Hexavalent chromium (Cr (VI)) is a known neurotoxin and environmental contaminant. Despite its recognition, the underlying mechanisms by which Cr (VI) induces neurological damage remain insufficiently explored. The complexities of the Central Nervous System (CNS), including the Blood Brain Barrier (BBB) and supporting brain cells, contribute to regions-specific susceptibility within the brain. Understanding Cr (VI) neurotoxicity is crucial for its potential role in neurodegenerative diseases.

A Systematic Review was conducted using international databases (PubMed, Medline, Scopus, and Web of Science) and Google Scholar. Only open-access, free full-text articles published in English between 2010 and 2025 were included. Following PRISMA 2020 guidelines, a total of 19 relevant studies were selected, comprising 12 animal-based and 7 human cohort studies.

Animal studies investigated the effects of Cr (VI) via various administration methods and doses, revealed evidence of oxidative stress, inflammatory markers, and apoptotic changes in the brain. Interventional studies showed delayed toxicity when antioxidant agents were used prior to Cr (VI) exposure, including PDC (Potassium Dichromate), SA (Sodium Alginate), and TNG (Tangeretin). Human studies, including autopsies and cell culture analyses, demonstrated neurotoxic effects in conditions such as ALS (Amyotrophic Lateral Sclerosis), nAMD (Neovascular Age-Related Macular Degeneration).

Animal studies have clarified the role of oxidative stress in Cr (VI)-induced neurotoxicity. Human cohort studies have identified Cr (VI) as an environmental risk factor for both neurodegenerative and neurobehavioral disorders. Future research should focus on defining harmful levels of Cr (VI) and exploring potential antioxidant therapies.