Lycium barbarum Extract Enhanced Neuroplasticity and Functional Recovery in 5xFAD Mice via Modulating Microglial Status of the Central Nervous System
Zhongqing Sun
Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
Innovation Research Institute, Xijing Hospital, Fourth Military Medical University, Xi'an, China
Department of Ophthalmology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, SAR, China
Department of Orthopaedics and Traumatology, School of Clinical Medicine, Li Kai Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
Search for more papers by this authorJinfeng Liu
Department of Ophthalmology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, SAR, China
Search for more papers by this authorZihang Chen
Department of Psychology, The University of Hong Kong, Hong Kong, SAR, China
Department of Sports Medicine, the First Affiliated Hospital, Jinan University, China
Search for more papers by this authorKwok-Fai So
Department of Ophthalmology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, SAR, China
State Key Lab of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China
Key Laboratory of CNS Regeneration, Guangdong-Hongkong-Macau CNS Regeneration Institute, Ministry of Education, Jinan University, Guangzhou, China
Search for more papers by this authorCorresponding Author
Yong Hu
Department of Orthopaedics and Traumatology, School of Clinical Medicine, Li Kai Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
Orthopedics Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
Correspondence:
Yong Hu ([email protected])
Kin Chiu ([email protected])
Search for more papers by this authorCorresponding Author
Kin Chiu
Department of Ophthalmology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, SAR, China
Department of Psychology, The University of Hong Kong, Hong Kong, SAR, China
State Key Lab of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China
Correspondence:
Yong Hu ([email protected])
Kin Chiu ([email protected])
Search for more papers by this authorZhongqing Sun
Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
Innovation Research Institute, Xijing Hospital, Fourth Military Medical University, Xi'an, China
Department of Ophthalmology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, SAR, China
Department of Orthopaedics and Traumatology, School of Clinical Medicine, Li Kai Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
Search for more papers by this authorJinfeng Liu
Department of Ophthalmology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, SAR, China
Search for more papers by this authorZihang Chen
Department of Psychology, The University of Hong Kong, Hong Kong, SAR, China
Department of Sports Medicine, the First Affiliated Hospital, Jinan University, China
Search for more papers by this authorKwok-Fai So
Department of Ophthalmology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, SAR, China
State Key Lab of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China
Key Laboratory of CNS Regeneration, Guangdong-Hongkong-Macau CNS Regeneration Institute, Ministry of Education, Jinan University, Guangzhou, China
Search for more papers by this authorCorresponding Author
Yong Hu
Department of Orthopaedics and Traumatology, School of Clinical Medicine, Li Kai Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
Orthopedics Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
Correspondence:
Yong Hu ([email protected])
Kin Chiu ([email protected])
Search for more papers by this authorCorresponding Author
Kin Chiu
Department of Ophthalmology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, SAR, China
Department of Psychology, The University of Hong Kong, Hong Kong, SAR, China
State Key Lab of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China
Correspondence:
Yong Hu ([email protected])
Kin Chiu ([email protected])
Search for more papers by this authorFunding: This work was supported by Joint Founding Project of Innovation Research Institute (LHJJ24JH13). Midstream Research Program for Universities (MRP-092-17X). Health and Medical Research Fund, Hong Kong, China (14151281).
ABSTRACT
Objective
Alzheimer's disease (AD) is the most prevalent neurodegenerative disease with limited treatment options. This study aimed to investigate the effects of Lycium barbarum extract (LBE), a Chinese herb, on the central nervous system (CNS)—including the retina, brain, and spinal cord—in 5xFAD transgenic mice after the onset of AD.
Methods
Starting at 6 months of age, 5xFAD mice received daily intragastric gavage of LBE (2 g/kg) for 2 months. At 8 months, behavioral tests were conducted to assess cognition, motor function, and visual function. These included the Morris water maze, novel object recognition, and Y-maze tests for cognition; the beam walking balance and clasping tests for motor function; and electroretinogram (ERG) for visual function. Immunohistochemistry, western blotting, and ELISA were used to evaluate Aβ deposition, microglial morphology, neuroinflammation, and neuroprotective signaling pathways. Primary microglia and the IMG cell line were used to study LBE's effects on Aβ uptake and degradation in vitro.
Results
After 2 months of LBE treatment, the decline in cognition, motor, and visual functions in 5xFAD mice was significantly slowed. Microglia in the brain, spinal cord, and retina exhibited a neuroprotective state, with reduced Aβ deposition, decreased inflammatory cytokine levels (e.g., TNF-α, IL-1β, IL-6), increased Arg-1/iNOS ratio, and enhanced phagocytic capacity. LBE also promoted Aβ uptake and degradation in primary microglia and the IMG cell line. Neuroprotective signals such as p-Akt, p-Erk1/2, and p-CREB were elevated. Additionally, LBE treatment restored synaptic protein expression and enhanced neuroplasticity.
Conclusion
The findings suggest that LBE treatment can enhance neuroplasticity, reduce systemic inflammation, and improve phagocyte clearance of Aβ deposition via inducing a neuroprotective microglial phenotype throughout CNS. As an upper-class Chinese medicine, appropriate intake of LBE may serve as a beneficial antiaging strategy for AD.
Conflicts of Interest
The authors declare no conflicts of interest.
Open Research
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Supporting Information
| Filename | Description |
|---|---|
| cns70123-sup-0001-Figures.docxWord 2007 document , 4.9 MB |
Figure S1. LBE oral feeding restores cognitive memory in 5xFAD mice. (A) The latency for the mice to reach the platform during the first 5 days of trials (n = 25 WT, n = 19 water treatment, n = 21 LBE treatment, **p < 0.01, two-way ANOVA with Tukey's multiple comparison test). (B)Total distance of day 6 in the swimming pool. (C) Mean speed of day 6 in the swimming pool (n = 25 WT group, n = 19 5xFAD group, n = 21 5xFAD + LBE group, one-way ANOVA with Tukey's multiple comparison test). (D) Illustration of the open-field test that measured the exploratory and spontaneous locomotor activity. (E) Time spent in the center of the square box (n = 25 WT group, n = 19 5xFAD group, n = 20 5xFAD + LBE group, Kruskal–Wallis test with Dunn's multiple comparison test). (F) Total distance in the center of the square box (n = 25 WT group, n = 19 5xFAD group, n = 20 5xFAD + LBE group, one-way ANOVA with Tukey's multiple comparison test). (G) Mean traveling speed in the square box (n = 25 WT group, n = 19 5xFAD group, n = 20 5xFAD + LBE group, one-way ANOVA with Tukey's multiple comparison test). (H) Illustration of the NOR test that measured the recognition memory. (I) Time spent on two objectives of the NOR test. (J) Recognition index in the NOR test. Figure S2. LBE oral feeding restores motor movement and retina responses in 5xFAD mice. (A) Representative picture of 5xFAD and WT mice in clasping test. The limbs exhibit clasping with curled toes in the 5xFAD mice at the position of white arrow. The limb clasping test was used to quantify deficits in corticospinal function. (B) Qualify the score of clasping tests. (C) Representative ERG waveform to a scotopic 0.01 cd.s/m2 flash under light adaptation of WT group (dark), 5xFAD (red), and 5xFAD + LBE (blue). (D, E) Scattered plots of the amplitude of a-wave and b-wave in the ERG of different groups under dark adaptation and flash in 0.01 cd.s/m2. (F) Representative ERG waveform to a scotopic 3.0 cd.s/m2 flash under light adaptation of WT group (dark), 5xFAD (red), and 5xFAD + LBE (blue). (G, H) Scattered plots of the amplitude of a-wave and b-wave in the ERG of different groups under dark adaptation and flash in 3.0 cd.s/m2. Figure S3. LBE treatment reduced Aβ load in the brain and spinal cord of 5xFAD mice. (A) Images of brain slices stained for Thio-S (green) labeling Aβ plaques from WT mice. Regions including DG and CA1 of the hippocampus, and cortex are shown in the different rows for WT mice. (B) Images of spinal cord slices stained for Thio-S (green) labeling Aβ plaques from WT mice. Scale bar: 50 μm. Figure S4. LBE treatment reduced Aβ load in the brain 5xFAD mice. (A) Representative image of 4G8 antibody for amyloid plaques in the hippocampus. Qualification of 4G8 protein level in the hippocampus. (B) Representative image of Aβ1-42 antibody for amyloid plaques in the hippocampus. Qualification of Aβ1-42 protein level in the hippocampus. (C) Representative image of 4G8 antibody for amyloid plaques in the cortex. Qualification of 4G8 protein level in the cortex (n = 4 WT group, n = 4 5xFAD group, n = 4 5xFAD + LBE group, one-way ANOVA with Tukey's multiple comparison test). (D) Representative image of 4G8 antibody for amyloid plaques in the spinal cord. Qualification of 4G8 protein level in the spinal cord. (E) Representative image of Aβ1-42 antibody for amyloid plaques in the spinal cord. Qualification of Aβ1-42 protein level in the spinal cord. (F) Representative image of 4G8 antibody for amyloid plaques in the retina. Qualification of 4G8 protein level in the retina (n = 4 WT group, n = 4 5xFAD group, n = 6 5xFAD + LBE group, one-way ANOVA test with Tukey's post hoc test.) ns, not significant. *, p < 0.05; **, p < 0.01. Figure S5. LBE treatment preserved presynaptic density in the CNS of 5xFAD mice. (A) Representative images of antibodies for SYP (presynapse) in brain after LBE treatment. (B) Qualification protein level of SYP in the hippocampus and cortex. Data are shown as mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001 by one-way ANOVA test with Dunn's multiple comparison test. Figure S6. LBE treatment preserved postsynaptic density in the CNS of 5xFAD mice. (A) Images of brain slices stained PSD95 (red) labeling presynaptic density from WT, 5xFAD, and 5xFAD + LBE mice. (B) Quantification of the relative density and counts of PSD95-positive dot points in the DG region. (C) Quantification of the relative density and counts of PSD95-positive dot points in the CA1 region. Scale bar: 20 μm. (D) Images of brain slices stained PSD95 (red) labeling presynaptic density from WT, 5xFAD, and 5xFAD + LBE mice. (E) Quantification of the relative density and counts of PSD95-positive dot points in the cortex region. (F) Images of spinal cord slices stained PSD95 (red) labeling presynaptic density from WT, 5xFAD, and 5xFAD + LBE mice. Scale bar: 20 μm. (G) Quantification of the relative density, and counts of PSD95-positive dot points in the spinal cord. (H) Images of retina slices stained for PSD95 (red) labeling presynaptic density merged with DAPI from WT, 5xFAD, and 5xFAD + LBE mice. (I) Quantification of the fluorescence intensity of PSD95-positive in the retina. Scale bar: 20 μm. Data are shown as mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001 by one-way ANOVA test with Tukey's multiple comparison test. |
| cns70123-sup-0002-DataS1.pdfPDF document, 1.5 MB |
Data S1. Supporting Information. |
Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
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