Mouse Model Of Pure Autonomic Failure Induced By ?-Synuclein Fibrils Seeding In Stellate Ganglion And The Underlying Mechanism

BackgroundPure autonomic failure(PAF)is a pure autonomic dysfunction without any motor disorders in ?-Synucleinopathies which include Parkinson's disease(PD),dementia with Lewy bodies(DLB),multiple system atrophy(MSA),and PAF.The pattern and manifestation of synucleinopathies are related to differences in cellular deposition and neuronal populations affected by ?-synuclein aggregation.Autonomic dysfunction is common in ?-synucleinopathies,while the mechanisms remain unknown.To date,no mouse model recapitulating pure autonomic dysfunction without motor dysfunction has been developed.ObjectiveThis study intends to generate a mouse model with pure autonomic dysfunction caused by stellate ganglionic injection of ?-synuclein fibrils,recapitulating pure autonomic dysfunction without any motor dysfunction.Method1.The preparation and transmission electron microscopy imaging of ?-Syn PFFs.2.Male TgM83+/-mice(8 weeks of age)were randomly divided into two groups with 20 mice in each group.?-Syn PFFs or PBS were injected into the bilateral stellate ganglia of mice in the model group and control group,respectively.3.The brain,spinal cord,stellate ganglion,myocardium and skin of mice were reserved at 8 weeks,12 weeks,16 weeks and 20 weeks after inoculation of ?-Syn PFFs or PBS with stellate ganglia,respectively.4.We used IH,IF and WB to observe the formation and propagation of?-Syn-positive inclusions in autonomic nervous pathway.5.The mice were evaluated by the cardiovascular(the heart rate and blood pressure),olfactory(the food burial test),sweeting function to assess the autonomic function,and motor function(rotarod test,footprint test,hanging wire test and beam walking test)at 8 weeks,12 weeks,16 weeks and 20 weeks after injection of ?-Syn PFFs or PBS with stellate ganglia.Result1.?-Syn PFFs after sonication were 67.56±41.86 nm.2.At 4 weeks post-injection(wpi),we detected scattered p?-Syn-positive neuronal bodies and axonal profiles in the stellate ganglia.3.At 8 wpi,a few scattered p?-Syn inclusions were detected in autonomic pathways.4.P?-Syn pathology became more condensed and intense at 12 wpi in ?-Syn PFFs mice compared to the PBS mice.5.At 12 wpi,the levels of blood pressure in the upright position were significantly decreased in ?-Syn PFFs mice compared with PBS mice(P<0.01).6.At 16 wpi,?-Syn PFFs mice developed hypohidrosis(P<0.0001).7 ?-Syn PFFs mice showed hyposmia at 16 wpi(P<0.0001).8.All of mice did not display any motor dysfunctions.Conclusion1.?-Syn fibrils into stellate ganglia of TgM83+/-mice induced spreading of?-Syn pathology to both the central autonomic nervous system and the autonomic innervation of peripheral organs through the autonomic pathway.2.?-Syn fibrils into stellate ganglia of TgM83+/-mice developed various autonomic dysfunction,such as orthostatic hypotension,constipation,hypohidrosis and hyposmia,without motor dysfunctions.