Fig. 1

Cell viabilities in three experimental groups assessed by MTT assay. a cell viability assays were performed at 24 h of incubation with various concentrations of glutamate. The viabilities of the cells were reduced to 94.2 ± 0.6, 85.2 ± 1.4, 72.0 ± 1.6, 54.2 ± 1.6, and 42.5 ± 2.4% with the glutamate at 2, 4, 6, 8, and 10 mM concentrations. N = 10 in each group. **p < 0.01 versus control by Student’s t test. b Cell viability after 6, 10 and 24 h of glutamate (6 mM) incubation with or without concurrent addition of selenium (100 nM). After 10 h of incubation, cell viabilities were reduced to 85.8 ± 2.5% by glutamate and the reduction was moderately improved by selenite (92.2 ± 1.3%). F(3, 23) = 13.6 and p < 0.001 by ANOVA. After 24 h of culture, glutamate further reduced the cell viability to 68.9 ± 3.9%, while selenite rescued the viability to 83.6 ± 1.5%. F(3, 23) = 18.9. *p < 0.05, **p < 0.01 versus control and ^## p < 0.01 versus glutamate by ANOVA with post hoc Tukey’s test. Glu glutamate, Se sodium selenite, Glu + Se = glutamate + sodium selenite. N = 6 in each group