Figure 1. Effects of THSG on glutamate-induced DNA fragmentation and excitotoxicity. C6 neural glioma cells were treated with various concentrations of THSG (10, 30, or 100 μM) for 2 h and then treated with L-glutamate (20 mM) for 24 h. C6 glioma cell morphology images are shown in (A). Cells treated with 20 mM L-glutamate for 24 h caused drastic cell death, as demonstrated by the poor and shrunken cell morphology. Scale bar = 100 μm. Cell viability measured by the MTT assay is shown in (B) (n = 4). Note: THSG significantly rescued glioma neural cells from glutamate neurotoxicity, and the best effective dose of THSG was 100 μM, which completely prevented glutamate-induced cell death. NS = no significant difference; ** P > 0.01; *** P < 0.001 between the groups. Statistical analysis was performed using ANOVA for repeated measures followed by Tukey’s test of least significant difference. NS = no significantly difference; *, P > 0.05; **, P < 0.01; ***, P < 0.001. (C) Gel electrophoresis showing the effects of THSG at a range of concentrations (3-300 μM) on L-glutamate-induced DNA fragmentation in glioma neural cells.