en Clinical Toxicology Clinical Toxicology Systematic Review <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><b>&nbsp;&nbsp;</b><b><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp; Background: </span></span></b><span style="font-size:9.0pt"><span style="font-style:normal">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. </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Methods:</b> 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. </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Results:</b> 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). </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Conclusion:</b> 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. </span></span></span></span></span></span></span></span><br> &nbsp; Chromium, Toxicity, Heavy metals, Neurodegenerative disorders, Oxidative stress, Neuroinflammation 1397 1407 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-9687-1&slc_lang=en&sid=1 Marat Iztleuov maratiztleuov11@gmail.com 200319475328460095454 200319475328460095454 No West Kazakhstan Marat Ospanov Medical University, Aktobe, Kazakhstan Nazerke Abugaliyeva nazerkeabugalievaaa@inbox.lv 200319475328460095455 0009-0009-9721-7006 Yes West Kazakhstan Marat Ospanov Medical University, Aktobe, Kazakhstan Sergey Ryzhkin rsa777@inbox.ru 200319475328460095456 200319475328460095456 No Medical Academy of Continuous Professional Education, Kazan State Medical University, Moscow, Kazan, Russia Yerbolat Iztleuov begemot888@gmail.com 200319475328460095457 200319475328460095457 No West Kazakhstan Marat Ospanov Medical University, Aktobe, Kazakhstan Samat Saparbaev samat-saparbayev@mail.ru 200319475328460095458 200319475328460095458 No MC Al-Jhami, Aktobe, Kazakhstan Gaziza Smagulova smagaziza@gmail.com 200319475328460095459 200319475328460095459 No West Kazakhstan Marat Ospanov Medical University, Aktobe, Kazakhstan