Effects of Qi-fu-yin on Improving Cognitive Impairment and Reducing Cellular Senescence in the Brains of 5xFAD Mice

Although the mechanism of Qi-fu-yin (QFY), a traditional Chinese medicine prescription, remains incompletely understood, it has shown therapeutic potential in Alzheimer's disease (AD). This study aimed to investigate the association between QFY treatment and cognitive impairment in 5xFAD mice. We used grip strength, gait, colony nesting, shuttle box, Morris water maze test, and ELISA to evaluate the levels of Amyloid-β protein 1-42 (Aβ1-42), Aβ1-40, Growth-associated protein 43 (GAP-43), Synaptophysin (SYN), and Postsynaptic density protein 95 (PSD-95) in the brains of 5xFAD mice. Luminex cytokine analysis was used to quantify Senescence-associated secretory phenotype (SASP) levels in the cortex. The amount of Senescence-associated β-galactosidase (SA-β-Gal), Aβ deposition, and dendritic spines in the animals' brains was measured by SA-β-Gal staining, immunohistochemistry, and Golgi-Cox staining, respectively. QFY treatment dramatically reduced cortical Aβ plaque burden and decreased p21 expression in 5xFAD mice, according to immunofluorescence tests. In 5xFAD mice, QFY therapy markedly enhanced learning and memory performance, alleviated aging, and increased the amounts of GAP-43, PSD-95, and SYN proteins in the mice's cortex. Following QFY treatment, there was a significant decrease in Aβ plaque and SA-β-Gal activity in the brain, as well as Aβ1-42 and Aβ1-42/Aβ1-40 levels in the hippocampus. The levels of IL-1α, IL-1β, IL-6, IL-17A, and IFN-γ were considerably reduced in the cortex of the 5xFAD mice. PCA and Pearson correlation analyses demonstrated a strong negative association between SASP cytokines and synaptic protein levels. These findings suggest an association between QFY treatment and improvements in age‑related cognitive decline and cellular senescence phenotypes in 5xFAD mice, alongside mitigated synaptic structural damage. These findings support further investigation of QFY as a potential therapeutic candidate for Alzheimer's disease.