Disulfide HMGB1 reduces overall cell and NG2 + cell counts in vitro. (A) Addition of disulfide HMGB1 at concentrations of 10 ng/ml, 100 ng/ml and 500 ng/ml significantly reduced overall cell counts compared to control conditions. (B) Disulfide HMGB1 significantly reduced NG2+ cell counts in all experimental conditions, in a dose dependant manner. For multiple different conditions, a two‐way ANOVA and one-way ANOVA with Dunnett's multiple comparison test was used. p values of < 0.05 were considered significant (*p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001). cNSPCs = rat cortical neural stem cell progenitors; DIV = days in vitro.