CPPs recovered the loss of synaptic proteins and synaptic plasticity in APP/PS1 mice. Synaptic proteins and spine density were evaluated in APP/PS1 mice after IG administration of 100, 300 mg/kg of CPPs or saline as control for one month. (A) Levels of PSD95, and synaptotagmin (SYT) were detected by western blotting in the hippocampus and GAPDH was used as loading control. (B, C) Quantitative analysis of the blots. (D) Representative Golgi staining images. (E) The quantification of spine density and (F) Mushroom type spine. P value significance is calculated from a one-way ANOVA. The data were expressed as mean ± SEM, *P < 0.05, **P < 0.01 vs. WT mice, #P < 0.05, ##P < 0.01, ###P < 0.001 vs. positive control (APP/PS1 mice without CPPs treatment), n = 3.