Fig. 1: Microglia elicit a long-lasting brain-resident inflammatory response after MCAO.
a,b, Representative T2-weighted MRI images (a) and quantification (b) of persistent ischaemic lesion quantified across the entire brain at acute and chronic stages after MCAO; n = 3 mice per group. c,IBA1 immunostaining reveal a significant increase in resident microglia at days 3, 7, 30, 90 and 180 after MCAO. For each image, the right panel shows a higher-magnification image of the lesion core (highlighted by the dashed white rectangle. d, Quantitative data of IBA1+ cell numbers in c across acute and chronic stages of MCAO; n = 3 mice per group. e, Schematic illustration of cerebral infarction and corresponding microglial morphological changes in the lesion core and peri-lesion regions. f, IBA1 immunostaining showing microglial morphology in the lesion area at days 3, 7, 14, 30, 90 and 180 post MCAO in male mice. Asterisks indicate foamy microglia. g,h, Quantification of morphological parameters, including soma volume (g) and filament length (h), is shown for MCAO-3d, MCAO-7d, MCAO-14d, MCAO-30d, MCAO-90d and MCAO-180d (n = 20 cells from three mice each) and sham (n = 23 cells from three mice). i, IBA1 immunostaining of human brain samples from a patient with ischaemic stroke (n = 1) and a healthy control (n = 1). Dashed white squares indicate regions shown at higher magnification. j, Heatmap showing upregulation of inflammatory genes in microglia isolated at 3, 30 and 90 days post MCAO compared to sham control; n = 4 mice per group for sham and MCAO-30d groups; n = 3 mice per group for MCAO-3d and MCAO-90d groups. k, GSEA showing upregulation of inflammatory and immune response pathways in microglia at both acute and chronic stages post MCAO. Normalized enrichment scores (NES) and P values are displayed; n = 4 mice per group for sham and MCAO-30d groups; n = 3 mice per group for MCAO-3d and MCAO-90d groups. RES, running enrichment score; RLM, ranked list metric. Data are mean and s.d. Statistical significance was assessed using one-way ANOVA (b,d,g,h) followed by Dunnett’s multiple comparisons test, or a one-sided permutation test, and the resulting P values were adjusted for multiple comparisons (k).
