关键词: 神经元, 谷氨酸, 硫酸镁

Abstract: To investigate the protective effects of magnesium sulfate on glutamate-induced neurotoxicity in cultured cochlear. Methods The cortis of newborn rats were cultivated in vitro. The cultured cochlear neurons were divided into glutamate group treated with 0.1 mmol•L^-1 glutamate,magnesium sulfate group treated with different concentrations of magnesium sulfate(0.5,1.0,2.0 and 4.0 mmol•L^-1) and combined group treated with glutamate and magnesium sulfate for 24 h. Immunofluorescence staining of Neurofilament 200kDa antibody was used to label spiral ganglion neuron(SGN) and the terminate of dendrites. The morphological changes of SGN were examined by fluorescent microscope and the amount of SGN was determined. In addition,the SGN was loaded with 10 μmol•L^-1 Fluo-3 /AM,and the intracellular Ca²⁺was measured by laser confocal scanning microscope (LCSM). Results Many SGN were smaller and swelling and vacuoles at the terminate of dendrites following glutamate treatment for 24 h. In combined group treated with glutamate and 0.5,1.0 and 2.0 mmol•L^-1 of magnesium sulfate,the amounts of SGN in creased compared with glutamate group(P<0.01).Under the concentration of 2 mmol•L^-1, magnesium sulfate was safe to SGN survival. Magnesium sulfate reduced the calcium influx of SGN from 0.5 to 4 h following glutamate treatment. Compared with glutamate group,the significant decrease of cell fluorescence intensity of SGN was observed in combined group(P<0.01). Conclusion Magnesium　 sulfate provides protective effects against SGN damage by glutamate-induced neurotoxicity.It can inhibit intracellular Ca²⁺ accumulation.

Key words: neurons, glutamic acid, magnesium sulfate