臺灣博碩士論文加值系統

老化、發炎和降低的腦源性神經滋養因子(BDNF)與黑質腦區中多巴胺神經元減少有關。然而，因果關係目前還不是很清楚。我們發現在老化老鼠中抑制微小膠細胞活化可減少老化相關多巴胺神經減少。BDNF和BDNF的接受器TrkB表現量與多巴胺神經元的數目成正比，但與微小膠細胞活化程度成反比。BDNF有效減弱脂多醣引起的微小膠細胞活化，而給予微小膠細胞shTrkB的處理後會抑制由BDNF引起的抗微小膠細胞活化。施予老鼠中強度的運動訓練，上調BDNF和TrkB的表現量，能抑制與老化相關的微小膠細胞活化和多巴胺神經元減少。給予老鼠顱內注射shTrkB抑制經由運動對抗微小膠細胞活化以及運動的神經保護效果，總結，我們發現多巴胺神經元、BDNF、微小膠細胞三者間互相調節的平衡關係。老化破壞三者間的平衡，有利於微小膠細胞活化。長期接受運動訓練的老鼠會上調BDNF和TrkB的表現並抑制老化相關的微小膠細胞活化及多巴胺神經元死亡。

Aging, inflammation, and reduced brain-derived neurotrophic factor (BDNF) are associated with dopaminergic neuron loss in the substantia nigra. However, the causal relationships are unclear. We found age-related dopaminergic neuron loss lower in mice with inhibited microglial activation. BDNF and BDNF-receptor TrkB levels were positively correlated with the number of dopaminergic neurons and negatively with the degree of microglial activation. Lipopolysaccharide-induced microglial activation was attenuated by BDNF, while BDNF-induced antimicroglial activation was inhibited by shTrkB treatment. In mice forced to exercise, which upregulates BDNF and TrkB, age-related microglial activation and dopaminergic neuron loss were inhibited. Microglial activation was higher and exercise-induced protection lower in mice treated with shTrkB. In conclusion, our findings suggest a three-way reciprocal regulation among dopaminergic neurons, BDNF, and microglia. Aging disrupts the balances among them and favors microglial activation. BDNF-TrkB signaling was upregulated and age-related microglial activation and dopaminergic neuron death were inhibited in mice forced to undergo long-term exercise.

Abstract in Chinese......................................I
Abstract................................................II
Acknowledgement........................................III
Table of Contents.......................................IV
List of Figures........................................VII
Abbreviations...........................................IX
Chapter 1: Introduction..................................1
1.1. Parkinson’s disease.................................1
1.2. PD and Inflammation.................................1
1.3. The role of resting or activated microglia in the
brain...............................................2
1.4. Microglia activation and DA neuron damage...........2
1.5. Aging and inflammation..............................3
1.6. Brain-derived neurotrophic factor and DA neuron
survival............................................4
1.7. Brain-derived neurotrophic factor and inflammation..5
1.8. Exercise prevents neuron loss and up-regulating
BDNF................................................6
1.9. Objectives and hypothesis...........................7
1.10.Experimental designs................................8
Chapter 2: Materials and Methods........................10
2.1. Animals............................................10
2.2. Beam traversal test................................10
2.3. Rotarod test.......................................11
2.4. Grasping strength test.............................11
2.5. Ki20227 and LPS treatment..........................11
2.6. Ibuprofen supplement...............................12
2.7. Treadmill running (TR) training....................12
2.8. Wheel running (WR) procedure.......................13
2.9. Preparation of TrkB shRNA and gene-expressing
lentivirus.........................................13
2.10.Delivering shTrkB to the brain.....................14
2.11.BDNF supplement and LPS treatment..................15
2.12.BV2 microglial cell culture........................15
2.13.Mesencephalic primary microglial cell culture......16
2.14.TrkB expression knockdown in BV2 cells.............17
2.15.TH-positive neuron culture.........................17
2.16.TH neuron toxicity assay...........................18
2.17.Preparing brain tissue.............................18
2.18.Immunohistochemistry...............................18
2.19.Counting cells.....................................19
2.20.Quantifying microglial area........................20
2.21.Dual immunofluorescenct staining and confocal
microscopy.........................................20
2.22.Transmission electron microscopy...................21
2.23.Quantifying TNF-a and IL-6 in the SN and in the
conditioned medium of microglial cells.............22
2.24.Western blotting...................................22
2.25.Flow Cytometry.....................................23
2.26.Statistical analysis...............................24
Chapter 3: Results......................................25
3.1. Age-related DA neuron loss, motor dysfunction, and
microglial activation..............................25

3.2. LPS-induced and Age-related DA neuron loss was lower
in mice in which microglial activation had been
inhibited..........................................27
3.3. Age-related downregulation of BDNF and TrkB........28
3.4. Microglial activation was inhibited by BDNF........28
3.5. Age-related DA neuron loss, motor deficit, microglial
activation, and downregulation of BDNF and TrkB were
ameliorated in running mice........................30
3.6. Effect of termination of treadmill running (TR) or
long-term wheel running (WR) on exercise-induced
neuroprotection and anti-microglia activation......31
3.7. BDNF-TrkB signaling is involved in TR-induced
neuroprotection and anti-microglial activation.....32
Chapter 4: Discussion...................................33
Chapter 5: Conclusion...................................38
Chapter 6: References...................................39
Chapter 7: Figures......................................48
Chapter 8: Publications.................................80

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