Fig. 4

Induced Siglec-E is neuroprotective after ischemia–reperfusion injuries. A Primary neuron–glia cultures derived from cortices of wild type or Siglec-E knockout mouse embryos were subjected to oxygen–glucose deprivation (OGD) for 1.5, 3, or 4.5 h. Following reoxygenation with full nutrition supply for 16 h, the cell viability in these cultures was measured and compared (n = 8–24, *p = 0.0172, two-way ANOVA with post hoc Šidák multiple comparisons). Data are presented as mean ± SEM. B Intraluminal filament-based middle cerebral artery occlusion (MCAO) model was utilized to examine the effects of genetic ablation of Siglec-E on cerebral ischemia. In this study, adult wild type and Siglec-E knockout male mice (12–14 weeks old) were subjected to transient MCAO for 30 min, which was followed by reperfusion for 72 h. C Siglec-E mRNA expression in the ipsilateral brain tissues of mice subjected to 30-min MCAO and 72-h reperfusion was measured by qPCR and compared to that of sham cohort (n = 7–14, ****p < 0.0001, Mann–Whitney U test). Data are visualized using box plot. D Neurological deficits of wild type and Siglec-E knockout mice after MCAO were evaluated at multiple time points using Bederson’s scale (n = 12–16, ***p < 0.001, two-way ANOVA). Data are presented as mean ± SEM. E Deficiency of Siglec-E in mice exacerbated post-stroke weight loss (n = 12–16, ***p < 0.001, two-way ANOVA with post hoc Šidák multiple comparisons). Data are presented as mean ± SEM. F Triphenyltetrazolium chloride (TTC) staining was performed to measure the brain infarction in wild type and Siglec-E knockout mice 72 h after MCAO. Representative images from each cohort are shown. The viable brain parenchyma appeared reddish, whereas the infarcted areas were pale and highlighted. G The volumes of brain infarcts in wild type and Siglec-E knockout mice were quantified and compared (n = 10–14, *p = 0.022, Mann–Whitney U test). Data are presented as mean ± SEM. H Animal mortality over 72 h following transient MCAO for 30 min (n = 14–17, p = 0.5734, log-rank test)