Regulation And Mechanism Of SNPH On Hippocampal Synaptic Changes In PTSD Mice

Post-traumatic stress disorder(PTSD)is a serious mental disorder that occurs and persists after a major traumatic event,and the research on PTSD has attracted much attention at home and abroad,but its specific pathophysiological mechanism is still unclear.Synaptic plasticity refers to the renewal and change of synaptic connections in neurons in form and function.It was found that the change of hippocampal synaptic plasticity was closely related to the occurrence and development of PTSD,and there were many genes involved in regulating hippocampal synaptic plasticity,and the regulatory mechanism was complex.Syntaphilin(SNPH)is an axonal mitochondrial anchor protein expressed in mature neurons,and the normal state can lock mitochondria to specific locations in the cell to ensure energy supply and thus maintain the stability of axonal mitochondria.In the pathological state,SNPH releases mitochondria through mitochondrial transport to transport them to the damaged area,providing energy for damage repair.SNPH knockdown enhances mitochondrial transport and cellular energy levels,promoting damaged neuronal regeneration and functional recovery.It suggests that SNPH may be involved in the occurrence of PTSD by regulating synaptic plasticity,but it has not been reported.Therefore,this study intends to use CRISPR-Cas Rx to target the expression of knockdown SNPH,observe its role in PTSD synaptic changes,explore the feasibility of using SNPH as a target for PTSD,and then provide new therapeutic targets and treatment strategies for PTSD and other mental disorders.Main research content:1.Establishment of PTSD mouse model and ICV injection of AAVSixty-eight female C57BL/6J mice were randomly divided into four groups,Control group,AAV-Cas Rx-SNPH/SPS group,AAV-Cas Rx-Lacz/SPS group and PTSD group,with 17 mice in each group.Animal models of PTSD were prepared by Single-prolonged stress(SPS),and AAV-Cas Rx-SNPH/SPS group and AAV-Cas Rx-Lacz/SPS group were injected with AAV-Cas Rx-SNPH and AAV-Cas Rx-Lacz virus in the lateral ventricles.2.Effects of targeted knockdown of SNPH on the behavior of PTSD miceThe behavior of each group of mice was tested by open field experiment,elevated cross maze experiment and Morris water maze experiment.3.Protective effect of targeted knockdown SNPH on neurons in PTSD miceHE and Nissl staining were used to observe the morphology and number of hippocampal neurons in each group,and immunofluorescence was used to detect the expression of neuronal marker NeuN protein.4.Effects of targeted knockdown of SNPH on synaptic plasticity in PTSD miceThe expression levels of Synapsin I and PSD95 proteins in the hippocampus of each group were detected by immunofluorescence or western blotting,and the changes of dendrites and dendritic spines in hippocampal neurons were observed by Golgi staining.5.Effects of targeted knockdown of SNPH on axonal regeneration in PTSD miceThe expression levels of MAP-2,GAP43 and NF200 proteins in the hippocampus of mice in each group were detected by immunofluorescence or Western bolt technology.6.Effect of targeted knockdown of SNPH on hippocampal ATP content in PTSD miceUltraviolet spectrophotometry was used to detect the change of ATP content in hippocampal tissues of each group.Key findings and conclusions:1.Mouse animal models of PTSD were successfully prepared,and the expression of mouse hippocampal SNPH protein was successfully reduced by lateral ventricle injection of AAV recombinant virus.2.Behavioral results showed that targeted knockdown of SNPH significantly improved the state of tension and anxiety and spatial learning and memory impairment of PTSD mice.3.After the mouse was stimulated by SPS,the tissue morphology of the hippocampus changed,and the phenomenon of neuronal nuclear contraction and Nissosome disappearance appeared,and the expression of neuronal marker Neu N was down-regulated.AAV-Cas RxSNPH virus injection can reverse the above situation and have a protective effect on hippocampal neurons in PTSD mice.4.SPS stimulation can damage the morphology of mouse hippocampal neuronal dendritic morphology,and downregulate the expression of synaptic plasticity-related proteins Synapsin I and PSD95,and injection of AAV-Cas Rx-SNPH virus may improve hippocampal neuron morphology by increasing the total length of hippocampal dendrite and dendritic spine density of PTSD mice,thereby promoting synaptic plasticity of mouse hippocampal neurons.5.The axon length of mice became shorter and the density decreased,which damaged the morphology of mouse neurons and significantly reduced the expression of axon-related proteins MAP-2,GAP-43 and NF200 after the preparation of PTSD animal model by SPS method.Targeted knockdown of SNPH may promote hippocampal neuronal axon regeneration by regulating the expression of GAP-43 and NF200 in PTSD mice.6.Compared with the control group,the total ATP content of the hippocampus of PTSD mice was significantly increased,and it was reduced after SNPH knockdown treatment.