Figure 6. PADK treatment reduces accumulation events in 10–11-month APP_SwInd mice.

APP_SwInd mice were treated with 9 daily injections of either PADK (20 mg/kg; n = 13) or vehicle (veh; n = 10), and wildtype mice (wt; n = 13) were injected with vehicle for 9 days. Fixed brain sections were stained with the 6E10 antibody; arrows denote extracellular deposits (A). Size bar: 450 µm. sg, stratum granulosum; sp, stratum pyramidale. Sections were also immunostained with an Aβ_1–42–specific monoclonal antibody; arrows denote CA1 cell bodies with intracellular labeling (B; size bar: 15 µm). The remaining tissue was separated for rapid homogenization, and equal protein aliquots of hippocampal samples were assessed by immunoblot. The 6E10 antibody labeled the 4-kDa Aβ species and the parent APP, and selective antibodies were used to label sAPPα, sAPPβ, and actin (C). Positions of molecular weight standards are shown. Mean integrated optical densities±SEM were normalized to 100% in vehicle-treated transgenic samples (–) to allow comparison of PADK effects (+) across the different antigens (D). The samples were also tested with an Aβ_x-42 sandwich ELISA to determine femtomoles of Aβ_1–42–related peptides per milligram protein (E). ANOVA: P<0.0001; post hoc test compared to APP_SwInd+vehicle: *P<0.01.