In vitro toxicity induced by methylmercury on sympathetic neurons is reverted by l-cysteine or glutathione

Abstract

Methylmercury (MeHg) is related to several deleterious effects on the vertebrate nervous system and part of these effects are through interaction with sulfhydryl (–SH) group found in cellular proteins. We decided to characterize the dose-dependent effect of MeHg on the neurotoxicity and the neurite outgrowth induced effects on chick sympathetic neurons dissociated and purified in culture. In this model, MeHg inhibited neurite outgrowth (1–10 μM) and induced cell death (1–10 μM) after 48 h in culture. Since metal toxicity often generates reactive oxygen species, we tested if antioxidant compounds such as glutathione (GSH) or l-cysteine ( l-cys) could block the deleterious effects promoted by MeHg. l-Methionine, another sulfur-containing amino acid, but without a SH group, was also used in this work. We show that GSH (10–100 μM) and l-cys (100 μM), but not l-methionine (100 μM), fully blocked neurite degeneration and sympathetic neuron cell death in culture.