Study On The Mechanism Of Injecting α-synuclein-positive Inclusion Body And Spreading Along Axons In Mouse Olfactory Bulb

BackgroundParkinson’s disease(PD)is a common neurodegenerative disease in the elderly,and it is also one of the most common synucleinopathies.The typical motor symptoms of Parkinson’s disease are known as resting tremors and bradykinesia.Muscle rigidity,posture gait disturbance,also known as four major sports sign.Olfactory disorders,autonomic dysfunction,sleep disorders,and cognitive dysfunction are typical non-motor symptoms of Parkinson’s disease and are also referred to as non-motor four main symptoms.Typical PD pathology is degeneration of lobar dopamine neurons and deposition of Lewy bodies in the brain;α-synuclein is the major component of Lewy body(LB)stained by eosinophils in dopaminergic neurons.Louis has a variety of protein in vivo,including α-synuclein,parkin,ubiquitin,etc.Among them,α-synuclein is the main component.The α-synuclein-positive inclusion body in neurons is the main pathological change,namely the abnormal cytoplasm content composed of misfolded α-synuclein.Mainly involving the nigrostriatal dopaminergic neurons,including noradrenergic and brain stem,5-HT neurons.Alpha-synuclein is a soluble protein that undergoes alpha-helix changes when bound to the membrane.Under pathological conditions,it oligomerizes and accumulates in the fibrous body,which is arranged in a sheet rich in β-sheet structure.Braak found that in the developmental stage of different course of Parkinson’s disease patients,misfolded abnormally aggregated α-synuclein is systematically spread to different regions of the brain through axons in the nervous system: preclinical stage of Parkinson’s disease patients.Α-synuclein is mainly distributed in the enteric nervous system,vagal dorsal nucleus and olfactory bulb region;prodromal stage;misfolded α-synuclein mainly distributed in the substantia nigra,midbrain and basal ganglia;clinical stage: error Folded alpha-synuclein diffusely distributes throughout the cerebral cortex in patients with Parkinson’s disease.Previous autopsy results of patients with Parkinson’s disease suggest that the pathological marker in the brain,Lewy bodies(LB),follows the predicted anatomy and gradually spreads to the entire nervous system.Studies confirm that aggregated or misfolded alpha-synuclein can spread between neurons.It has been proposed that aggregated and misfolded α-synuclein can be transmitted in a prion-like manner in the human nervous system.The misfolded α-synuclein is then released outside the cell and re-uptaked by adjacent cells.After entering new cells,the misfolded α-synuclein can further be in the form of seed α-synuclein.Induces increased expression of pathological alpha-synuclein.That is,misfolded proteins act as a template that will cause the pathological protein of the disease to pass from one cell to another.This theory of misfolded α-synuclein transfer between cells contributes to Parkinson’s disease.And other synaptophysin diseases pathogenesis.Braak et al.The pathological study of scholars confirmed that α-synaptic protein was deposited on the olfactory bulb first,which is consistent with the conclusion that olfactory dysfunction occurred in early stages of Parkinson’s disease,suggesting that olfactory dysfunction may be related to the deposition of α-synapsein.In summary,it is speculated that the olfactory projection pathway is the main dissemination pathway of pathological α-synuclein in the nervous system of patients with Parkinson’s disease.We further investigated the injection of α-synuclein-positive inclusion bodies in the mouse olfactory bulb and along the nerve axis.The mechanism of sudden dissemination.ObjectiveIn this experiment,the mouse olfactory bulb was injected into the α-synuclein fibroblast model to study the mechanism of the formation of olfactory bulb α-synuclein positive inclusion bodies and spread along the axons.Methods1.The α-synuclein fibrin was prepared.2.The α-synuclein fibroblasts were injected into C57 BL / 6 mouse olfactory bulbs by stereotaxic method and were harvested on days 1,2,3,and 4.3.Immunohistochemical staining and double immunofluorescent histochemistry staining were performed on the various layers of the central nervous system of mice at 1,2,3,and 4 days,and the olfactory bulbs and their fibers were observed by electron microscopy and immunofluorescence microscopy.The formation and dissemination of brain α-synuclein-positive inclusion bodies in neurons,microglia and other cells.Results1.The α-synuclein fibrin was prepared and its morphology was identified under transmission electron microscope.2.Two days after the mouse olfactory bulb was injected with α-synuclein fibroblasts,the formation of α-synuclein-positive inclusion bodies was detected in the olfactory bulb(OB)and the pre-olfactory nucleus(AON).3.Four days after the mouse olfactory bulb was injected with α-synuclein fibroblasts,the formation of α-synuclein-positive inclusion bodies was detected at the contact cortex(FrA)and the pyriform cortex(PIR)levels.4.Alpha-synuclein-positive inclusion bodies colocalize with neurons and microglia.Conclusion1.The α-synuclein fibroids can form positive inclusions in the central nervous system and spread along the olfactory neural projection pathway.2.The formation of α-synuclein-positive inclusion bodies activates phagocytosis of microglia.