Di Huang Yi Zhi Fang improves cognitive function in APP/PS1 mice by inducing neuronal mitochondrial autophagy through the PINK1-parkin pathway

BACKGROUND: Alzheimer's disease (AD) is an irreversible age-related neurodegenerative condition characterized by the deposition of amyloid-β (Aβ) peptides and neurofibrillary tangles. Di Huang Yi Zhi (DHYZ) formula, a traditional Chinese herbal compound comprising several prescriptions, demonstrates properties that improve cognitive abilities in clinical. Nonetheless, its molecular mechanisms on treating AD through improving neuron cells mitochondria function have not been deeply investigated. OBJECTIVE: This study administered DHYZ to APP/PS1 mice to explore its potential therapeutic mechanisms in AD treatment. METHODS: APP/PS1 transgenic mice were given DHYZ (L, M, H), donepezil, or distilled water for a consecutive 12-week period. The Morris water maze test was used to assess memory capacity, transmission electron microscopy was used to observe mitochondrial and synaptic structures, immunohistochemistry and western blot detected proteins involved in the mitochondrial autophagy pathway, ELISA measured serum Aβ content, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assessed neuronal cell apoptosis. RESULTS: DHYZ demonstrates a notable therapeutic impact on mice with AD, effectively improving cognitive and memory impairments. DHYZ decreases Aβ accumulation in the hippocampus by reducing BACE1 activity and enhancing Aβ clearance through the blood-brain barrier. Additionally, DHYZ significantly suppresses neuronal apoptosis, enhances synaptic structure, and increases synapse numbers, processes strongly linked to the activation of mitochondrial PINK1-Parkin autophagy. CONCLUSIONS: DHYZ enhances cognitive function in APP/PS1 mice by stimulating neuronal mitochondrial autophagy through the PINK1-Parkin pathway.