Rat B35 neuroblastoma cell lines stably expressing miR negative (Y168), miR-negative with SUMO-1 shRNA#2, SUMO-2,3 microRNA (Y241) alone, and SUMO-2,3 miRNA with SUMO-1 shRNA#2 were incubated with quercetin at 20 and 40 μM for 16 hr, and the levels of SUMO-conjugation and cellular tolerance to OGD/ROG were examined. (A) Representative immunoblots (upper panel) and their quantitative analyses (lower panel). (B) Cell death after OGD/ROG (for 16hr/5hr respectively) was measured via LDH release and is shown as percentages of control (Y168 cells without quercetin, DMSO alone). Data represent the mean ± standard deviation of at least three independent experiments. ****p<0.0001, ***p<0.001, **p<0.01, *p<0.05 compared to the DMSO alone control via a one way ANOVA, followed by Dunnett’s post-hoc test.