Fig. 4

Hyperglycemic condition increases the vulnerability of brain to peripheral inflammatory stimulation

(A) Representative flow cytometric analysis of brain cell populations in vehicle- and STZ-treated mice followed by an intraperitoneal injection of LPS (0.5 mg/kg, 6 h). (B-E) Quantification of each cell population in (A). (6 mice, STZ-LPS; 7 mice, other groups) (F-G) Quantification of mRNA levels of IL-1𝝱 and TNF-𝝰 in the brain extracts of veh- or STZ-treated mice upon PBS or LPS injection (0.5 mg/kg, 3 h). (5 mice, veh-PBS; 6 mice, veh-LPS, STZ-LPS; 8 mice, STZ-PBS) (H-I) Representative brain images (H) and quantification (I) of relative Evans blue extravasation into brain of veh- or STZ-treated mice upon LPS administration (0.5 mg/kg, 6 h). Evans blue was intravenously injected one hour before sacrifice. (5 mice, veh-PBS; 13 mice, veh-LPS; 12 mice, STZ-PBS; 11 mice, STZ-LPS) (J) Heatmap of astrocytes endfoot genes (GO:0097450) in RNA-seq data from veh- or STZ-treated mice. Asterisk indicates genes of FDR adjusted p-value < 0.05. (K) Quantification of mRNA level of Aqp4 (aquaporin 4) in the brain extracts of veh- or STZ-treated mice. (5 mice, vehicle; 8 mice, STZ group) (L) Representative immunohistochemical images of hippocampal region of veh- or STZ- treated mice followed by LPS administration (0.5 mg/kg, 6 h). The coronal brain sections were stained with anti-GFAP (red) and anti-Iba1 (green). DAPI represents nuclear signal (blue). Scale bars = 50 μm. (M-O) Quantification of mean fluorescence intensity of Iba1 (M) or GFAP (N), and the number of Iba1 cells (O) per DAPI. (7 mice, veh-LPS; 8 mice, STZ-LPS) Data are presented as means ± SEM. Asterisks indicate significant differences between the groups as determined by two-way ANOVA with Bonferroni post hoc test (B-G and I) or Student’s two-tailed, unpaired t test (K and M-O); *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, n.s. not significant