Figure 9

Histological analysis of biomarkers in the brain. Top half of Figure: effect of D-Ala2 glucose-dependent insulinotropic polypeptide (GIP) treatment on synaptic density on 6-month-old APP/PS1 mice and wild type (WT) age-matched littermates. Quantification of levels of expression of synaptophysin in (A) the exterior neocortex (layers 1 to 3), and (B) the interior neocortex (layers 4 to 6). Data show mean ± standard error of the mean (SEM) of six mice per group (one-way analysis of variance, ANOVA, **P < 0.01). Quantification of levels of expression of synaptophysin in (C) the polymorphic layer of the dentate gyrus (DG), (D) the granular cell layer of the DG, (E) the molecular layer of the DG, (F) the stratum radiatum, (G) the stratum pyramidal and (H) the stratum oriens. Data show mean ± SEM of six mice per group (one-way ANOVA, * P < 0.05; ** P < 0.01; *** P < 0.001). Representative images of synaptophysin stained-brains of WT mice (scale bar: 440 μm). The photographs on the top row show the polymorphic layer of the DG (a), the granular cell layer of the DG (b), the molecular layer of the DG (c), the stratum radiatum (d), the stratum pyramidal (e) and the stratum oriens (f). On the micrograph, interior neocortex (g) and exterior neocortex (h) stained against synaptophysin is shown. Bottom half of Figure: effect of D-Ala²GIP treatment on synaptic density on 12-month-old APP/PS1 mice and WT age-matched littermates. Quantification of levels of expression of synaptophysin in (A) the exterior cortex, and (B) the interior cortex. Data show mean ± SEM of six mice per group (one-way ANOVA). Hippocampus: (C) the polymorphic layer of the DG, (D) the granular cell layer of the DG, (E) the molecular layer of the DG, (F) the stratum radiatum, (G) the stratum pyramidal and (H) the stratum oriens. Data show mean ± SEM of six mice per group (one-way ANOVA). * P < 0.05; **P < 0.01; ***P < 0.001.