Icariin improves the cognitive function of APP/PS1 mice via suppressing endoplasmic reticulum stress

This study aimed to investigate the effect of icariin (referred as ICA) on Alzheimer's disease (AD) model through endoplasmic reticulum (ER) stress pathway.

Nine months male APP/PS1 and wild-type (WT) mice were randomly divided into four groups: APP/PS1 control, APP/PS1 + ICA, WT control and WT + ICA groups. The treated mice were given ICA 60 mg/kg/d and control mice were received the same volume distilled water for consecutive 3 months. The Morris water maze and Novel object recognition were used to detect animals' behavior. Nissl staining was used to observe the neuronal morphology in hippocampus area. Aβ deposition in hippocampal region was observed by immunofluorescence staining. TUNEL staining was used to observe apoptosis. Detection of expression of ER stress related factors by Western blot and real time RT-PCR.

Chronically administrated with ICA compared with APP/PS1 control mice significantly improved the behavior performance, reduced neuronal apoptosis, as well as suppressing the ER stress signaling pathway, including that decreased the level of glucose-regulated protein 78, phosphorylated ER-regulated kinase and phosphorylated eukaryotic initiation factor α, as well activating transcription factor-4, C/EBP homologous protein, DNA damage inducible protein 34 and tribbles homologous protein 3.

Our data indicated that ICA suppressed the ER stress signaling to protect against AD animal model, these findings suggest that a potential point for researching the effect of ICA on neurodegeneration.