**Figure 2.** **Differential profiles of the gut microbiota between SAMR1 and SAMP8 mice.** (**A**) Heat map of differential levels of bacteria between the groups. (**B**) Chao 1 index (*t*-test, *P* < 0.01). (**C**) Shannon index (*t*-test, *P* < 0.05). (**D**) Simpson index (*t*-test, *P* > 0.05). (**E**) PCoA analysis of gut bacteria data (Bray–Curtis dissimilarity). (**F**) PCA analysis of gut bacteria data. α-diversity data are shown as mean ± SEM (n = 10). PCA: principal component analysis; PCoA: principal coordinates analysis. **P* < 0.05, ***P* < 0.01.