Investigating Structural Synaptic Plasticity In Early Ischemic Stroke By Immunohistochemistry And Proteomics

Objective:Severe stroke patients may experience brain tissue structural damage and neuronal death,further leading to functional disorders in the affected area and even irreversible damage.The hyperacute phase of stroke has significant clinical significance,as treatment interventions within this time frame largely determine long-term prognosis.However,there is relatively little attention paid to synaptic changes within the stroke time window(within 4.5 hours).If we study stroke from the perspective of studying synaptic structure and function,and discover the specific mechanisms of structural and functional changes,it is beneficial for us to find new targets for treating stroke within the time window.Therefore,exploring the impact of changes in synaptic structure and function in the ultra early stage of stroke has very important clinical significance.The aim of this study is to explore the plasticity of synaptic structures during ultra early ischemic stroke.Methods:Establish an MCAO model using the thread bolt method,which is an in vivo model;Establish an OGD model using oxygen glucose method,which is an in vitro model;Using immunohistochemical methods to detect the effects of MCAO induced synaptic structural proteins(Bassoon,Homer,v Glut1,Glu A2,Glu N1,Cav2.1);Using immunofluorescence assay to detect the effects of OGD induced synaptic structural proteins(Bassoon,Homer,Glu N1,Glu A2);Extract synaptosomes from MACO experimental rats using Syn-PER reagent kit;Using the TMT protein quantification method,differential proteins were screened,and GO analysis and KEGG analysis were performed on the screened differential proteins.Results:Within 4 hours,we found that MCAO induced the slow loss of Bassoon in the presynaptic active area of the infarcted area and penumbra of the cerebral cortex,and the rapid loss of Homer in the postsynaptic compact area.The degree of damage to the structural protein in the postsynaptic compact area was greater than that in the presynaptic active area;MCAO induced structural enhancement of the presynaptic active area and postsynaptic dense area in the contralateral cortex of the infarcted area;MCAO induced increased expression of glutamate transporter 1 in the central infarct area and penumbra area of the cerebral cortex,and proteomic results showed that glutamate synaptic protein was enhanced;At the same time,the AMPA receptor subtype Glu A2 was significantly lost in the core infarct area and penumbra area of the cerebral cortex,and the expression level of NMDA receptor subtype Glu N1 was increase.The synaptic structural proteins Bassoon,Homer,Glu N1,and Glu A2 induced by OGD were all reduced.Conclusion:In the ultra early stage of ischemia,the structures of the presynaptic active area and postsynaptic dense area in the contralateral cortex of the ischemic area are enhanced,and the structural damage to the presynaptic active area in the ischemic cortex is lighter than that in the postsynaptic dense area.The glutamate transport function is significantly enhanced in the ischemic zone.During the ultra early stage of cerebral stroke,there were significant changes in ionic glutamate receptors,with a significant decrease in AMPA receptor subtype Glu A2 protein expression on the ischemic side of the cortex;The expression of NMDA receptor subtype Glu N1 protein is increased.This study aims to investigate the changes in synaptic structure during the stroke window period,providing reference for the study of synaptic function changes and mechanisms,and also providing some ideas for the treatment of stroke diseases.