Fig. 6

Ligature-induced periodontitis increased immune responses in the gums and the brains of 3 × Tg-AD mice. a Schematic illustration of the experimental timeline. b Representative images of the stained maxillary jaws from 3 × Tg-AD mice in each group viewed at both buccal and palatal sides. Yellow bars represent the distance from the cementoenamel junction (CEJ) to the alveolar bone crest (ABC). c Quantitate measurements of the vertical bone loss (mm) from CEJ to ABC at both buccal and palatal sides. Data are presented as mean ± SEM (n = 5). Statistical analysis was done using two-way ANOVA with Tukey’s post-hoc test. d The total bacterial load detectable within gum tissues was measured by 16S rRNA real-time PCR at 5 weeks post-ligation. Data are present as mean ± SEM (n = 4). e Relative mRNA expression levels of inflammatory mediators in the gums of 3 × Tg-AD mice in each group. f Relative mRNA expression levels of inflammatory mediators in the hippocampus, frontal cortex, and hypothalamus of 3 × Tg-AD mice in each group. Data are presented as mean ± SEM (n = 7–8). g Representative images of immunofluorescence staining for Iba-1-positive microglia (green) and DAPI (blue) in the cortex, sub-regions of the hippocampus, and thalamus of 3 × Tg-AD mice in each group. h Representative images of immunofluorescence staining for GFAP-positive astrocytes (red) and DAPI (blue) in the cortex, sub-regions of the hippocampus, and thalamus of 3 × Tg-AD mice in each group. i, j Quantification of (i) Iba-1 and (j) GFAP immunofluorescence intensity in the cortex, sub-regions of the hippocampus, and thalamus of 3 × Tg-AD mice in each group. Data are presented as mean ± SEM (n = 5–6). Statistical analysis was done using unpaired t test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001