Protective role of taurine against morphine-induced neurotoxicity in C6 cells via inhibition of oxidative stress.

This study was carried out to investigate the protective role of taurine (2-aminoethanesulphonicacid) against morphine-induced neurotoxicity in C6 cells. It was found that taurine significantly increased the viability of C6 cells treated by morphine, showing the neuroprotective role against morphine-induced neurotoxicity. However, such neuroprotective effect of taurine could not be blocked by bicuculline, an antagonist of gamma-amino butyrate (GABA) receptor. To determine the oxidative damage induced by morphine, the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were measured in C6 cells. The decreased activities of SOD, CAT, and GPx in C6 cells were observed after morphine treatment for 48 h. However, taurine administration effectively ameliorated morphine-induced oxidative insult. To estimate anti-apoptosis effect of taurine, flow cytometry analysis as well as detection for caspase-3 and Bcl-2 expressions was performed after morphine exposure for 48 h. It was found that Bcl-2 expression was down regulated by morphine, whereas taurine could reverse morphine-induced decrease in Bcl-2 expression. Taurine showed no effect on caspase-3 expression. Collectively, the results show that taurine possesses the capability to ameliorate morphine-induced oxidative insult and apoptosis in C6 cells, probably due to its antioxidant activity rather than activation of GABA receptors.