Effect of NMN on CA1 neuronal cell death induced by global cerebral ischemia. Cresyl violet staining of the post-ischemic hippocampal CA1 sector following 6 days of recovery (A). There is a major loss of CA1 pyramidal neurons in vehicle treated animals. In sham operated animals all the CA1 neurons appeared normal. NMN (62.5 mg/kg) treated animals also show normal neuronal morphology. Scale bar represents 50 μm. Quantification of uninjured CA1 neurons in hippocampus (B) shows that there is about 50% cell death at 6 days of recovery in vehicle treated animals. NMN administration at the start of recovery significantly improves the cells survival. The horizontal lines represent the mean value. The most efficient dose was 62.5 mg/kg (p < 0.0001). *p < 0.05; **p < 0.01, ***p < 0.001 when compared to vehicle treated group (n = 11), #p < 0.05, ##p < 0.01, ###p < 0.001 when compared to sham (n = 11), ANOVA followed by Bonferroni’s test.