Expression Of FABP7 In Epilepsy Models And Regulation Of Seizures

Background:Epilepsy is a common chronic nervous system disease that threatens human health,which is mainly characterized by repeated abnormal discharges of brain neurons.Its high incidence and high disability rate cause heavy social and economic burden.At present,the pathogenesis of epilepsy mainly involves ion channels,neurotransmitters,glial cells,synaptic proteins and synaptic plasticity.Among them,the current research hotspot is that astrocytes induce epilepsy by transporting neurotransmitters,regulating ion channels and participating in immune response.Fatty acid binding protein 7 is a kind of small molecular cytoplasmic protein,which is mainly expressed in hippocampal astrocytes.As a specific ligand of DHA,fatty acid binding protein 7 is involved in cell maintenance and proliferation.It has been proved that FABP7 plays a role in neurogenesis,gliosis,inflammation and other epilepsy-related neuropathology.It is speculated that FABP7 may be involved in the pathogenesis of epilepsy.Objective:To establish a mouse model of epilepsy induced by kainic acid(KainicAcid,KA)and to detect the expression of FABP7 in hippocampus and cortex of epileptic mice.Adeno-associated virus was used to overexpress and inhibit FABP7 respectively to observe the effect of FABP7 on seizures in KA model and to explore its effect on the formation and progression of epilepsy.Methods:Mainly used KA hippocampal injection to induce epileptic model;Western blotting and immunofluorescence to detect the temporal and spatial expression of FABP7,hippocampal stereotaxic injection of adeno-associated virus to interfere with FABP7 expression,continuous video monitoring and in vivo multi-channel EEG recording of seizures in mice and other experimental methods.Adult male C57BL/6 mice were selected and KA was injected into the hippocampus to induce epileptic animal model.Western blotting was used to detect the expression of FABP7 in epileptic group and control group,and immunofluorescence method was used to detect the expression of FABP7 in the brain.Adult male C57BL/6 mice were randomly divided into 4 groups:overexpression group(AAV-FABP7),overexpression empty virus group(con-AAV-FABP7),interference virus group(AAV-shFABP7)and interference empty virus group(con-shRNA).Adeno-associated virus was stereotaxically injected into the hippocampus and the transfection efficiency was detected.Three weeks after injection of virus,the KA epileptic model was established,and the latency and total duration of epileptic seizures in acute and chronic phase were recorded.After the end of behavior,the local field potential in the hippocampus was recorded by in vivo multi-channel technique,and statistical analysis was carried out to evaluate the differences of epileptic seizures among the groups.Result:In the acute and chronic phase of KA epileptic mice,the expression of FABP7 in hippocampus and cortex was higher than that in the control group(P<0.05).Immunofluorescence showed that FABP7 was mainly highly expressed in the hippocampus and partly in the cortex,and co-located with astrocytes and neurons.Adeno-associated viruses AAV-FABP7,con-AAV-FABP7,AAV-shFABP7 and con-shRNA were injected stereotactically into hippocampus.The transfection efficiency was detected by immunofluorescence after 3 weeks,and the results showed that GFP was positive in hippocampus.The transfection level was detected by Western blotting,and the optical density(OD)value of each group was compared.The OD value of overexpression group was significantly increased(P<0.05),while that of interference group was significantly decreased(P<0.05).Through behavioral analysis and field potential recording,the total duration of SRSs in the overexpression group was significantly longer than that in the control group,and the total duration of the interference group was significantly shorter than that in the control group(P<0.05).The latency of SRSs in the interference group was significantly shorter than that in the control group,while that in the overexpression group was significantly prolonged(P<0.05).Conclusions:The expression of FABP7 in the cortex and hippocampus of the KA model was significantly higher than that of the control group,suggesting that FABP7 may be involved in the process of epilepsy.Up-regulation of hippocampal FABP7 expression mediated by adeno-associated virus can promote the susceptibility and severity of seizures in KA mice;on the contrary,by interfering with hippocampal FABP7 expression,the opposite results were observed in KA mice,suggesting that FABP7 may be involved in the regulation of seizures.