Administration of QFY enhances learning and memory in 5xFAD mice
After QFY administration, a shuttle box test was conducted to assess the conditional active avoidance response of mice (Figure 2A–C). The results showed the number of active avoidances on days 1-4 (Figure 2A, p < 0.05) and the area under the curve (AUC) of active avoidance (Figure 2B, p < 0.01) during the learning period, and the number of active avoidances (Figure 2C, p < 0.05) during the test period were significantly reduced in 5xFAD mice compared with WT mice. The administration of donepezil and memantine significantly increased the number of active avoidances on day 2 during the learning period in 5xFAD mice (Figure 2A, p < 0.05). The administration of QFY significantly increased the number of active avoidances on days 3 and 4 (Figure 2A, p < 0.05), and the AUC of active avoidance (Figure 2B, p < 0.01 in QFY high-dose group) during the learning period, and the number of active avoidances (Figure 2C, p < 0.05 in QFY low-dose group) during the test period. This data indicates that the ability to perform an active avoidance response was impaired in 5xFAD mice, whereas QFY administration improved it.
We used the Morris water maze to evaluate spatial learning and memory in mice. The results showed (Figure 2D–I) that the escape latency on the first day (Figure 2D, p < 0.05) and AUC of escape latency (Figure 2E, p < 0.01) during learning period, escape latency in testing period (Figure 2F, p < 0.05) were obviously increased in 5xFAD mice compared with WT mice, the number of platform crossings (Figure 2H, p < 0.05) was reduced significantly in 5xFAD mice compared with WT mice. The administration of donepezil and memantine significantly reduced the AUC of escape latency during the learning period (Figure 2E, p < 0.05) and during the testing period (Figure 2F, p < 0.01). The treatment of QFY significantly reduced the AUC of escape latency during the learning period (Figure 2E, p < 0.05 in QFY low-dose and high-dose groups, p < 0.01 in QFY medium-dose group) and escape latency (Figure 2F, p < 0.01 in three QFY groups) during the testing period, and also prolonged the time in the target quadrant (Figure 2G, p < 0.05 in low-dose QFY group), increased the number of crossings (Figure 2H, p < 0.05 in low-dose QFY), evidently. These results indicate spatial learning and memory deficits in 5xFAD mice and that QFY treatment ameliorated these deficits.
Administration of QFY alleviates aging in 5xFAD mice
After QFY administration, gait, grip strength, and colony nesting tests were used to evaluate mouse aging. The results (Figure 3A) showed that, compared with WT mice, run duration, run maximum variation, and the step sequence regularity index decreased significantly in 5xFAD mice (p < 0.05). Run average speed (Figure 3A, p < 0.05), right forelimb (RF) stand index (Figure 3A, p < 0.01), left hindlimb (LH) stand index (Figure 3A, p < 0.05), RF max contact (Figure 3A, p < 0.01), right hindlimb (RH) swing speed (Figure 3A, p < 0.05), LH swing speed (Figure 3A, p < 0.01) and duty cycle (FIGURE 3A, p < 0.05) in 5xFAD was significant increased. The treatment of donepezil and memantine increased RH, stand index left forelimb (LF) stand index (Figure 3A, p < 0.05) and decreased LH duty cycle (Figure 3A, p < 0.01), also reduced RH initial dual stance (Figure 3A, p < 0.05) and LH terminal dual stance (Figure 3A, p < 0.01) of 5xFAD mice. The administration of QFY reduced LH duty cycle (Figure 3A, p < 0.05 in QFY low- and p < 0.01 in medium-dose group), RH initial dual stance (Figure 3A, p < 0.05 in QFY low-dose and high-dose group, p < 0.01 in QFY medium-dose group) and LH terminal dual stance (Figure 3A, p < 0.05 in QFY low-dose group, p < 0.01, in QFY medium- and high-dose group), also increased the run duration (Figure 3A, p < 0.05 in QFY low-and medium-dose group), run maximum variation (Figure 3A, p < 0.05 in QFY low- and medium-dose group), step sequence regularity index (Figure 3A, p < 0.01 in QFY low- and medium-dose group), LF stand index (Figure 3A, p < 0.05 in QFY low-dose group) and LH stand index (Figure 3A, p < 0.05 in QFY low-dose group) of 5xFAD mice. These results indicate that 5xFAD mice exhibited an abnormal gait, which QFY treatment restored.
After QFY administration, a grip-strength test was conducted to assess forelimb strength. The experimental data (Figure 3B) show that the forelimb strength of the 5xFAD mice was significantly weaker than that of WT mice (p < 0.01). The administration of donepezil and memantine (Figure 3B, p < 0.01), QFY (Figure 3B, p < 0.01, in QFY low-dose and high-dose groups) significantly increased the grip strength of the 5xFAD mice. These studies suggest that forelimb strength in 5xFAD mice has been enhanced by QFY treatment.
The results of colony nesting test showed (Figure 3C–G) that the nesting score of the 5xFAD mice were significantly lower than the WT mice at 6 h (Figure 3C, p < 0.05), 12 h and 24 h after the start of colony nesting (Figure 3DE, p < 0.01), and the untorn tissue weight was significantly higher of 5xFAD mice (Figure 3F, p < 0.01). Administration with donepezil and memantine just decreases the untorn tissue weight (Figure 3F, p < 0.01). The treatment with QFY increased nesting scores at 12 h (Figure 3D; QFY p < 0.05 in the QFY medium-dose group) and 24 h (Figure 3E; QFY p < 0.05 in the QFY low- and medium-dose groups). Moreover, the untorn tissue weight was significantly lower in the QFY low- and medium-dose groups (Figure 3F, p < 0.01) and in the QFY high-dose group (Figure 3F, p < 0.05). These results indicated that QFY treatment enhanced daily activity in 5xFAD mice.
Treatment of QFY reduces the synaptic structure damage in the cerebral cortex of 5xFAD mice
After QFY treatment, the cerebral cortex of mice was collected to measure the protein levels of GAP-43, PSD-95, and SYN by ELISA. The results (Figure 4A–C) showed that the contents of GAP-43 (Figure 4A, p < 0.05), PSD-95 (Figure 4B, p < 0.01), and SYN (Figure 4C, p < 0.01) in the cerebral cortex of the 5xFAD mice were significantly lower than those in WT mice. The protein content of GAP-43 (Figure 4A, p < 0.05), PSD-95 (Figure 4B, p < 0.01), and SYN (Figure 4C, p < 0.01) significantly increased after the treatment of QFY. The results of Golgi-Cox staining (Figure 4D) showed that the length of dendrites in the cerebral cortex of the 5xFAD mice was shorter (Figure 4G, p < 0.05) than that of WT mice. The treatment with QFY tended to increase the length, number, and density of dendritic spines.
Treatment of QFY reduced Aβ deposition and cellular senescence in the brains of 5xFAD mice
Aβ deposition and cellular senescence play important roles in AD pathogenesis. We used a combination of SA-β-Gal staining and Aβ immunohistochemistry to assess co-localization between SA-β-Gal and Aβ plaques. The result showed there was a large amount of SA-β-Gal aggregation and Aβ plaque deposition in the cerebral cortex of 5xFAD mice (Figure 5A), while only a few SA-β-Gal aggregations and Aβ plaque depositions were found after QFY treatment (Figure 5A). In addition, there was co-localization of SA-β-Gal and Aβ plaque.
Immunofluorescence assays revealed that 5xFAD mice brains were heavily laden with both Aβ plaques and p21-positive cells (Figure 5B,C). Administration of QFY significantly curtailed cortical Aβ plaque and attenuated p21 expression in these animals (Figure 5B,C). The results of ELISA showed that compared with WT mice, the content of Aβ1-42 and the ratio of Aβ1-42/ AΒ1-40 was significantly increased in the hippocampus of 5xFAD mice (Figure 5D,F, p < 0.01), while the treatment of QFY reduced them obviously (Figure 5D, p < 0.01; Figure 5F, p < 0.05, respectively).
Senescent cells typically secrete large amounts of SASP factors. The results of Luminex analysis showed the contents of IL-1α (Figure 5G, p < 0.05), IL-1β (Figure 5H, p < 0.01), IL-17A (Figure 5J, p < 0.05), CCL3 (Figure 5K, p < 0.01), CCL4 (Figure 5L, p < 0.01), CCL5 (Figure 5M, p < 0.01) and IFN-γ (Figure 5N, p < 0.01) were significantly increased in cortex of 5xFAD mice. QFY treatment decreased the contents of IL-1α (Figure 5G, p < 0.05), IL-1β (Figure 5H, p < 0.05), IL-6 (Figure 5I, p < 0.05), IL-17A (Figure 5J, p < 0.05), and IFN-γ (Figure 5N, p < 0.01) in the cortex significantly.
These data indicate that cellular senescence appeared in the brain of 5xFAD mice, while the treatment of QFY reduced cellular senescence in 5xFAD mice.
Effects of QFY ameliorating cognitive impairment and reducing the aging of brain cells in 5xFAD mice correlated with synaptic damage
Principal component analysis (PCA) was performed to assess the overall SASP expression profiles (IL‑1α, IL‑1β, IL‑6, IL‑17A, CCL3, CCL4, CCL5, and IFN‑γ) among WT, 5xFAD, and QFY‑treated groups (Figure 6A). The first two principal components accounted for 44.11% and 23.46% of the total variance, respectively. As shown in the PCA score plot (Figure 6A), the WT group was clearly separated from the 5xFAD group. Notably, the QFY‑treated group showed an intermediate position, clustering more closely with the WT group than with the 5xFAD group, suggesting partial normalization of the SASP profile after QFY treatment. Statistical analysis of PC1 scores (Figure 6B) revealed that the 5xFAD group exhibited significantly higher PC1 values than the WT group. PC2 scores (Figure 6C) also showed significant differences between the 5xFAD and WT groups. Loading plot analysis (Figure 6D) indicated that IL‑1α, IL‑1β, and IFN‑γ were the major contributors to PC1, whereas IL‑6 and CCL3 contributed more substantially to PC2.
We performed Pearson correlation analyses between IL-1α, IL-1β, and IFN-γ and the contents of PSD-95, GAP-43, and SYN in the cortex, as well as the contents of Aβ1-40 and Aβ1-42 and the ratio of Aβ1-42/Aβ1-40 in the hippocampus, and developed heatmaps to visualize the interplay between synaptic-associated protein and SASP function. IL-1α, IL-1β, and IFN-γ levels positively correlated with the contents of Aβ1-40 and Aβ1-42 and the ratio of Aβ1-42/Aβ1-40 (Figure 6E, p < 0.05), and negatively correlated with the content of SYN protein. The levels of IL-1α and IFN-γ were negatively correlated with the content of GAP-43 protein, and IL-1β was negatively correlated with PSD-95 protein (Figure 6E, p < 0.05). These data suggest that IL-1α, IL-1β, and IFN-γ are major contributors to synaptic dysfunction.
Data Availability:
All raw data supporting the findings of this study have been deposited in Figshare and are accessible via the private reviewer link: https://doi.org/10.6084/m9.figshare.33208029.

Figure 1: Schematic diagram of the experimental procedure. Please click here to view a larger version of this figure.

Figure 2: QFY administration improves learning and memory performance in 5xFAD mice. (A–C) Shuttle box test: (A) Number of active avoidance responses during the learning period. (B) Area under the curve (AUC) for active avoidance responses during the learning period. (C) Number of active avoidance responses during the test period. (D–I) Morris water maze test: (D) Escape latency during the learning period. (E) AUC for escape latency during the learning period. (F) Escape latency during the test period. (G) Time spent in the target quadrant. (H) Number of platform crossings. (I) Movement trajectories during the test period. Mean ± SD, n = 11–20 per group, with exact n indicated in each bar. * = p < 0.05, vs WT, Student`s t-test; # = p < 0.05, ## = p < 0.01, vs 5xFAD; One-way ANOVA followed by Dunnett's multiple comparisons test. Please click here to view a larger version of this figure.

Figure 3: Effects of QFY administration on aging-associated functional measures in 5xFAD mice. (A) Gait heat map. The color scale is based on row‑wise Z‑score normalization, where red indicates values above the group mean, blue indicates values below the group mean, and white represents the mean level. (B) Grip strength test. (C–G) Colony nesting test: (C) Nesting score 6 h, (D) Nesting score at 12 h. (E) Nesting score at 24 h. (F) Untorn tissue weight. (G) Representative images of nests at 24 h. Mean ± SD, n = 3 per group, with exact n indicated in each bar. * = p < 0.05, ** = p < 0.01, vs WT, Student`s t-test; # = p < 0.05, ## = p < 0.01, vs 5x FAD, One-way ANOVA followed by Dunnett's multiple comparisons test. Please click here to view a larger version of this figure.

Figure 4: QFY attenuates synaptic structural alterations in the cerebral cortex of 5xFAD mice. (A) Content of GAP-43 in the cortex. (B) Content of PSD-95 in the cortex. (C) Content of SYN in the cortex. (D) Golgi-Cox staining. (E) Number of dendritic spines. (F) Density of dendritic spines. (G) Dendritic length. Mean ± SD, n = 3–14 per group, with exact n indicated in each bar. * = p < 0.05, ** = p < 0.01, vs WT, Student`s t-test; # = p < 0.05, ## = p < 0.01, vs 5xFAD, Student`s t-test. Please click here to view a larger version of this figure.

Figure 5: QFY reduced Aβ deposition and cell senescence in the brains of 5xFAD mice. (A) Combined SA-β-Gal staining and Aβ immunohistochemistry, SA-β-Gal (green, blue arrow), Aβ (brown, red arrow), SA-β-Gal + Aβ (yellow arrow), n = 3, Scale bar = 10 µm, 20x objective. (B) Immunofluorescence images showing Aβ in the cerebral cortex after treatment of QFY, n = 3, Scale bar = 50 µm, 40x objective. (C) Immunofluorescence images showing p21in the cerebral cortex after treatment of QFY. n = 1, Scale bar = 50 µm, 40x objective. (D–F) ELISA. (D) Content of Aβ1-42 in the hippocampus. (E) Content of Aβ1-40 in the hippocampus. (F) Aβ1-42/ Aβ1-40. (G–N) Luminex cytokine analysis. (G) Content of IL-1α in the cortex. (H) Content of IL-1β in the cortex. (I) Content of IL-6 in the cortex. (J) Content of IL-17A in the cortex. (K) Content of CCL3 in the cortex. (L) Content of CCL4 in the cortex. (M) Content of CCL5 in the cortex. (N) Content of IFN-γ in the cortex. Mean ± SD, n = 8–14 per group, with exact n indicated in each bar. * = p < 0.05, ** = p < 0.01, vs WT, Student’s t-test; # = p < 0.05 ## = p < 0.01, vs 5xFAD, Student’s t-test. Please click here to view a larger version of this figure.

Figure 6: Principal component and correlation analyses of SASP factors, synaptic proteins, and Aβ levels in 5xFAD mice following QFY treatment. (A–D) Principal component analysis (PCA) of SASP factors. (A) PCA score plot. (B) PC1 scores. (C) PC2 scores. (D) PCA loading plot. (E) Heatmap generated from the correlation analysis between the SASP and PSD-95, GAP-43, SYN, Aβ1-40, Aβ1-42, and the ratio of Aβ1-42/Aβ1-40. Colors closer to red indicate higher R-values, while colors closer to white indicate lower R-values. Mean ± SD; n = 8 per group. * = p < 0.05, ** = p < 0.01,vs WT; ## = p < 0.01, vs 5xFAD, & = p < 0.05, && = p < 0.01, indicates a significant correlation. Pearson correlation analysis was used to assess associations between variables. Please click here to view a larger version of this figure.

Figure 7: Proposed model of the effects of QFY on age-related cognitive decline and cellular senescence-associated phenotypes in 5xFAD mice. Please click here to view a larger version of this figure.