Chromium Selectively Accumulates in the Rat Hippocampus after 90 Days of Exposure to Cr(VI) in Drinking Water and Induces Age- and Sex-Dependent Metal Dyshomeostasis

• Published in: Toxics (Basel) Vol. 12; no. 10; p. 722
• Main Authors: Vielee, Samuel T, Buchanan, William J, Roof, Spencer H, Kahloon, Rehan, Evans, Elizabeth, Isibor, Jessica, Patel, Maitri, Meaza, Idoia, Lu, Haiyan, Williams, Aggie R, Kouokam, J Calvin, Wise, Sandra S, Guo, Luping, Wise, Rachel M, Wise, Jamie L, Cai, Lu, Cai, Jun, Wise, Jr, John P
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 03-10-2024; MDPI
• Subjects: Age; Age differences; Bioaccumulation; Brain; Brain research; Carcinogens; Chromium; Contact dermatitis; Contaminants; Disease; Drinking water; Environmental protection; essential metals dyshomeostasis; Exposure; Females; Geriatrics; Heavy metals; Hexavalent chromium; Hippocampus; Homeostasis; Hypothalamus; Industrial pollution; Laboratory animals; Males; Mass spectrometry; Metals; Neurotoxicity; Pituitary gland; Pollution; Potassium; Rodents; Scientific imaging; Sex; sex differences; Toxicity; North Carolina; United States > US; age differences; neurotoxicity; essential metals dyshomeostasis; hexavalent chromium; sex differences
• ISSN: 2305-6304; 2305-6304
• DOI: 10.3390/toxics12100722

Hexavalent chromium (Cr[VI]) is a widespread environmental pollutant in air and water that is primarily attributed to industrial pollution. The current maximum contaminant levels (MCLs) for drinking water from the World Health Organization and the U.S. Environmental Protection Agency (0.05 and 0.1 mg/L, respectively) were set based on contact dermatitis and warrant further toxicological investigation. While Cr(VI) is neurotoxic and accumulates in the brain, most animal studies only report whole-brain Cr, leaving large knowledge gaps. Few studies consider differences between ages or sexes, and fewer consider essential metal dyshomeostasis. We sought to investigate where Cr accumulates in the brain, considering sex and age differences, following a 90-day drinking water exposure to current MCLs. Here, we report Cr levels in six brain regions of rats exposed to drinking water Cr(VI). We observed Cr only accumulated in the hippocampus, and only in older females. We further assessed changes to essential metals in the hippocampus, observing opposite effects across sexes and between young rats compared to older rats. In sum, our data indicate drinking water Cr(VI) selectively targeted the hippocampus, with geriatric females accumulating the most Cr, and induced significant essential metal dyshomeostasis even in tissues lacking evident Cr accumulation.