Using glial fibrillary acidic protein (GFAP) immunohistochemistry (IHC) we found that the percentage of hippocampal CA1 area covered by astrocytes in vehicle injected APP/PS1 mice was increased roughly twofold (WT vehicle: 4.63 ± 0.33, AD vehicle: 8.01 ± 1.32) compared to vehicle injected WT littermate controls (Figure 5). This evidence concerns the gene PSEN1 and Alzheimer disease.