Chuanxiong-Danggui herb pair alleviated cognitive deficits of APP/PS1 mice by promoting mitophagy

Disruption of receptor-mediated mitophagy contributes to neuronal damage in Alzheimer's disease (AD). Chuanxiong-Danggui herb pair (CDHP) is classic herbal pair applied to treating neurodegenerative diseases including AD, Amyotrophic Lateral Sclerosis, Parkinson's disease. Though studies have demonstrated the neuroprotective effects of CDHP, the underlying mechanisms by which CDHP attenuates neuronal impairment of AD remains to be elucidated.

The objective of this work was to investigate the anti-AD mechanism of CDHP in APP/PS1 mice.

Behavioral assessments were conducted on C57BL/6J and APP/PS1 mice following CDHP treatment, alongside an evaluation of neuronal morphology in the hippocampal region. In vitro, HT-22 cells were induced by Aβ_25-35 before being treated with CDHP. The mechanisms of CDHP were investigated using transmission electron microscopy, Golgi staining, immunofluorescence, and Western blot analysis.

Results from the passive avoidance test and the Morris water maze (MWM) indicated that CDHP significantly mitigated cognitive deficits of APP/PS1 mice, accompanied by a reduction of pathological damage in the CA1 and CA3 regions of hippocampus. Further testing found that a significant reduction in dendritic spines density was rescued by CDHP. Synaptophysin (SYN) and postsynaptic density protein 95 (PSD-95) were elevated in the CDHP group, while β-amyloid (Aβ) plaques deposition was significantly reduced. Simultaneously, CDHP markedly inhibited neuronal apoptosis through a decrease of the levels of Cleaved Caspase-12 and enhanced expression of Bcl-2/Bax, both in vivo and in vitro. Additionally, CDHP improved mitochondrial morphology and function in the AD model by decreasing abnormal mitochondria and increasing the expression of COXIV. Transmission electron microscopy (TEM) revealed that clear mitophagy-autophagosomes were nearly absent in APP/PS1 mice, while the expression of p62 and LC3B were elevated following CDHP treatment. Furthermore, CDHP increased the expression of the FUNDC1 and PGAM5 in APP/PS1 mice and AD-like cell models.

These findings suggest that CDHP mitigated cognitive dysfunction in APP/PS1 mice by enhancing mitophagy to reduce neuronal injury.