Methylmercury Neurotoxicity and Interactions with Selenium

Abstract

Methylmercury (MeHg) is a ubiquitous contaminant and potent neurotoxicant with no completely effective therapy, although selenium antagonises MeHg toxicity. Furthermore, nanoparticles are promising as a novel drug delivery system. We researched the potential of selenium nanoparticles (SeNPs) in antagonising MeHg neurotoxicity compared to selenomethionine (SeMet) using primary astrocyte cell cultures and examining outcomes related to oxidative stress. We found that SeNPs were more toxic than SeMet. Increasing SeNPs significantly decreased MeHg cellular uptake and MeHg significantly decreased uptake of SeNPs at the highest concentration. Finally, SeNPs alone produced significantly higher reactive oxidative species and altered the ratio of reduced-to-oxidised glutathione, but MeHg, SeMet, and co-exposures did not. There were no significant effects on glutathione peroxidase or reductase activity. This suggests that SeNPs are more toxic than MeHg in cerebellar astrocytes and that they may not be suitable as a therapy at the doses and formulation used in this research.