Disulfide HMGB1 inhibits oligodendrocyte progenitor cells proliferation with no effect on the overall survival. (A) Cell death was not significantly influenced by the presence of disulfide HMGB1. The addition of BoxA to cultures did not impact upon the proportion of PI + (dead) cells. Therefore, HMGB1, nor TLR4/2 blockade, affected overall cell death in these cell cultures. (B) NG2+ cell counts were significantly reduced in the presence of 100 ng/ml disulfide HMGB1 verses control cultures. (C) Disulfide HMGB1 at 100 ng/ml significantly reduced the mitotic index for NG2+ cells. For comparisons between two conditions, two-tailed student’s T-test was used, and 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.