Fig 6. 25-HC has a species-dependent, NMDAR-independent protecting effect on OGD-induced cell death.

(A) Survival rate in rat cultures was compared between control, OGD (3 hr), OGD (3 hr) + MK-801(20 μM), and OGD (3 hr) + MK-801(20 μM)+ 25-HC (20 μM). Cell death induced by more severe OGD (3 hr) was only partially inhibited by MK-801 application. 25-HC protected against the MK-801 insensitive OGD-induced cell death. (n = 12 cultures for each group, one-way repeated measures ANOVA with Sidak’s post hoc test, **P < 0.01, ***P < 0.001). As in other experiments with 25-HC, neuroprotection was modest but reliable across experiments. (B) SGE-201 did not increase cell death, verifying the NMDAR independence (N = 9 cultures for each group; P > 0.05). (C) H₂O₂ (100 μM, 1 hour treatment) toxicity was used to test neuroprotection of 25-HC. 25-HC again yielded mild but reliable protection (N = 10 cultures for each group, one-way repeated measures ANOVA with Bonferroni’s post hoc test, *P < 0.05). (D) and (E) Neither WT nor CYP46A1 KO hippocampal neuron cultures from C57Bl/6 mice was sensitive to the mild NMDAR independent neuroprotective effect of 25-HC (N = 7 cultures for each group; P > 0.05).