Effect Of Nogo-A Targeted Immunotherapy On Synaptic Plasticity Of Hippocampal Neurons In Ptsd Rats And Associated Mechanism

Posttraumatic stress disorder(PTSD)is a psychological dysfunction caused by the body’s fight against major diseases or stress.Its cure rate is low,the course of disease is long,it is not easy to detect,and in some severe cases,it even causes problems such as schizophrenia,depression,suicide etc,which causes long-term sustained economic burden and negative impact on individuals and society.Therefore,it is important to study the pathogenesis of PTSD and find effective therapeutic targets for the prevention and treatment of PTSD.Related experimental studies have shown that changes in hippocampal synaptic plasticity are important markers of PTSD.Nogo-A,as a nerve growth inhibitor,not only participates in the inhibition of axon growth,but also regulates hippocampal synaptic plasticity.Nogo-A is involved in the synaptic plasticity regulation through its receptors and downstream signaling pathways.As a result,the Nogo-A may be an important target for PTSD treatment.To investigate the effect and mechanism of Nogo-A on hippocampal neurons synaptic plasticity of PTSD rats.This experiment used a single-prolonged stress method to prepare PTSD animal model.In order to inhibit the expression of Nogo-A in vivo,PTSD rats were immunized with pcDNA-GMCSF-Nogo eukaryotic expression vector co-expressing Nogo-66,Amino-Nogo(including NogoΔ20)and GM-CSF mixed with liposome or nanogold.The therapeutic effect was evaluated by behavioral examination,hippocampal histopathological staining and Golgi staining,and the molecular mechanism was further studied by immunofluorescence and Western blot.The main research contents are as follows:1.Preparing PTSD animal model and immunotherapyFemale adult SD rats weighing 200±20g were randomly divided into three groups after preparation of PTSD animal model by SPS method: PTSD+pcDNA-GMCSF-Nogo+ liposome immunization group(GMCSF-Nogo/Liposomes IM group),PTSD + pcDNA – GMCSF – Nogo+ gold nanoparticles immunization group(GMCSF-Nogo/GNPs IM group)and PTSD group,and normal control group.2.Behavioral effects of Nogo-A nucleic acid vaccine on PTSD ratsBehavioral tests were performed on each group of rats in the open field,elevated plus maze and Morris water maze test.By comparing the differences between the behavioral data of each group,the therapeutic effect of immunization was evaluated preliminarily.3.Histopathological effects of Nogo-A nucleic acid vaccine on PTSD ratsThe morphological changes of axons,dendrites and dendritic spines in hippocampal neurons of rats in each group were observed by using Nissl staining,HE staining and Golgi staining,respectively.4.Molecular mechanism of the effect of Nogo-A nucleic acid vaccine on behavior of PTSD ratsTo explore the molecular mechanism of the effect of Nogo-A nucleic acid vaccine on behavior of PTSD rats,the expression of Nogo-A and its receptors such as NgR,PirB,S1PR2 and downstream signaling pathway-related proteins RhoA,ROCK and synaptic plasticity synapsin I and p-CREB was detected by using immunofluorescence staining and Western blot in hippocampus slices and hippocampus tissues of rats in each group.Main results and conclusions:1.PTSD animal model was successfully constructed by SPS method,and Nogo-A nucleic acid vaccine was injected intramuscularly,Nogo antibody was then produced successfully in immunized rats.2.The results of open field experiment,elevated cross maze experiment and water maze experiment showed that Nogo-A nucleic acid vaccine could improve anxiety and depression of PTSD rats,enhance curiosity and exploring ability,and improve motor,learning and memory ability.3.The results of Nissl staining,HE staining and Golgi staining showed that Nogo-A nucleic acid vaccine can improve the number and morphology of hippocampal vertebral neurons,increase the number and complexity of axons,dendrites,and increase the density of dendritic spines.These results suggest that Nogo-A nucleic acid vaccine may improve the behavior of PTSD rats by inhibiting hippocampal neuronal apoptosis and maintaining the morphology and number of axons,dendrites and dendritic spines.4.Immunofluorescence and Western blot analysis showed that Nogo-A nucleic acid vaccine could affect the expression of Nogo-A receptors and downstream signaling pathway-related proteins by inhibiting the expression of Nogo-A,which leads to up-regulation of synaptic plasticity related markers,and mediates hippocampal neurons synaptic plasticity changes to achieve therapeutic effect on PTSD.