Riluzole-Triggered GSH Synthesis via Activation of Glutamate Transporters to Antagonize Methylmercury-Induced Oxidative Stress in Rat Cerebral Cortex

OBJECTIVE This study was to evaluate the effect of riluzole on methylmercury- (MeHg-) induced oxidative stress, through promotion of glutathione (GSH) synthesis by activating of glutamate transporters (GluTs) in rat cerebral cortex. METHODS Eighty rats were randomly assigned to four groups, control group, riluzole alone group, MeHg alone group, and riluzole + MeHg group. The neurotoxicity of MeHg was observed by measuring mercury (Hg) absorption, pathological changes, and cell apoptosis of cortex. Oxidative stress was evaluated via determining reactive oxygen species (ROS), 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDAs), carbonyl, sulfydryl, and GSH in cortex. Glutamate (Glu) transport was studied by measuring Glu, glutamine (Gln), mRNA, and protein of glutamate/aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1). RESULT (1) MeHg induced Hg accumulation, pathological injury, and apoptosis of cortex; (2) MeHg increased ROS, 8-OHdG, MDA, and carbonyl, and inhibited sulfydryl and GSH; (3) MeHg elevated Glu, decreased Gln, and downregulated GLAST and GLT-1 mRNA expression and protein levels; (4) riluzole antagonized MeHg-induced downregulation of GLAST and GLT-1 function and expression, GSH depletion, oxidative stress, pathological injury, and apoptosis obviously. CONCLUSION Data indicate that MeHg administration induced oxidative stress in cortex and that riluzole could antagonize this situation through elevation of GSH synthesis by activating of GluTs.