Fuzhisan ameliorates cognitive ability in Alzheimer's disease by p62 and related autophagy regulatory pathways.

Background: Maintaining autophagic homeostasis has been proved to play an important role in Alzheimer's disease.

Object: The aim of this study was to investigate the effect of Fuzhisan(FZS) on autophagic function in Alzheimer's disease and to elucidate its potential mechanism through the P62 regulatory pathways.

Methods: FZS was extracted by water extraction-rotary evaporation method. The novel object recognition test, morris water maze test and Y maze test were used to observe the cognitive and memory ability of APP/PS1 mice. The effects of FZS on the ultrastructure of mice hippocampus were examined by transmission electron microscopy. Molecular level changes were also further detected, including Aβ deposition, tau hyperphosphorylation, SOD, CAT and autophagy related proteins (p62, Nrf2, keap1, mTOR, LC3II/I, Beclin1, Atgs).

Results: FZS could alleviate memory and cognitive impairment in APP/PS1 mice, increase the autophagic vesicles and organelle abundance in hippocampus. FZS also reduced the levels of Aβ and tau hyperphosphorylation in the hippocampus of model mice, upregulated the levels of SOD, CAT and autophagy related proteins (Nrf2, LC3II/LC3I, Beclin1, Atg7 and Atg12) as well as downregulated the expression of P62, keap1 and p-mTOR/mTOR proteins. Co-Ip results showed that FZS elevated the levels of p62/LC3 and P62-keap1-Nrf2 complex, but decreased the P62 and keap1 association.

Conclusion: Our findings indicate that FZS may affect autophagy function and oxidative stress by regulating P62 and related pathways to promote the clearance of Aβ and phosphorylated tau, thereby improving the cognitive ability of AD, which provided a novel perspective for exploring the potential mechanism of FZS upon AD.