The Mechanism Of BDNF-AS/BDNF/TrkB Pathway In Propofol-induced Rat Hippocampal Neuron Injury

Background:Propofol is a short-acting intravenous anesthetic with the advantages of fast onset of anesthesia induction and rapid recovery.It is one of the most commonly used intravenous anesthetics in clinical anesthesia.In the past,it was generally believed that propofol in clinical concentration and administration time did not damage the brain,but in recent years,more and more studies have shown that propofol may damage the differentiation of brain neurons and the growth of nerve synapses,thus affecting the long-term memory,learning and other functions of the brain.Hippocampal area is the area responsible for learning and memory in the brain.The damage of neurons in hippocampal area will reduce related functions.Brain derived neurotrophic factor(BDNF)is a neurotrophic protein synthesized mainly in the brain.It is widely involved in neurogenesis,synaptic plasticity and survival of neurons in the brain.Its expression content is the highest in the hippocampus,Biological effects are exerted by binding to receptors with strong affinity(Trk A,Trk B,trk C)or neurotrophin receptors with molecular weight of 75 KD(p75).Lnc RNA BDNF-AS is a relatively conserved long noncoding RNA,which can reverse regulate brain-derived neurotrophic factor(BDNF)to complete the biological functions of regulating neuronal survival,development and differentiation.Therefore,this study will explore whether propofol can damage hippocampal neurons and whether lnc RNA BDNF-AS is involved in the regulation of propofol induced hippocampal neuron injury and its mechanism.Methods:After subculture of HT22 mouse hippocampal neurons,hippocampal neurons were treated with different concentrations of propofol(12.5μM,25 μM,50 μM.100 μM))and different treatment time(12h、24h、48h).The blank group and propofol solvent DMSO group were set as the control group.The viability of neuronal cells was detected by CCK-8,the expression of BDNF-AS and BDNF m RNA was detected by real-time fluorescence quantitative PCR(q RT-PCR),western blotwas used to detecte the expression of BDNF protein,the apoptosis and damage of HT22 hippocampal neuronal cells was evaluated by Flow cytometry.In HT22 hippocampal neuronal cells,after knockdown of BDNF-AS,the knockout effect of BDNF-AS and the transcription of BDNF m RNA were verified by q RT-PCR,the expression of proteins BDNF,p-Trkb and Trk B were detected by western blot,the activity of neuronal cells was detected by CCK-8,to investigate the role of BDNF-AS/BDNF pathway in propofol-induced hippocampal neuron injury.In propofol induced hippocampal neuronal cells,Trk B antagonist ANA-12 was used,the apoptosis was detected by flow cytometry,the transcription of BDNF-AS and BDNF m RNA was detected by q RT-PCR,the viability of neuronal cells was detected by CCK-8,Western blot was used to detecte the expression of protein BDNF,p-Trkb / Trk B,cleaved Caspase-3,cleaved Caspase-7,cleaved Caspase-9,Bax and Bcl-2 to investigate the mechanism of BDNF/ Trk B pathway in propofol-induced rat hippocampal neuron injury.Results:Propofol has neurotoxicity and can induce damage to HT22 hippocampal neurons.The degree of damage increases with the increase of propofol concentration and treatment time.When the propofol concentration exceeds 50μM and treatment time was more than 24 hours,the apoptosis rate of HT22 hippocampal neurons increased and the cell viability decreased.BDNF-m RNA and protein BDNF decreased with the increase of propofol concentration and treatment time,and BDNF-AS increased with the increase of propofol concentration and treatment time.Knockdown of BDNF-AS can up-regulate the expression of BDNF-m RNA and BDNF protein,reduce the apoptosis of hippocampal neurons induced by propofol,increase cell viability,significantly up-regulate the level of Trk B phosphorylation,reduce the expression of apoptosis related protein(cleaved Caspase-3,cleaved Caspase-7,cleaved Caspase-9),increase the expression of anti-apoptotic protein Bcl-2 and reduce the expression of Pro-apoptotic protein Bax.After using Trk B antagonist ana-12 in propofol induced hippocampal neurons,the apoptosis rate increased,Trk B phosphorylation was inhibited,the expression of Bax and cleaved Caspase-3,cleaved Caspase-7,cleaved Caspase-9 increased,and the expression of Bcl-2 decreased.Conclusion:Propofol has a toxic effect on HT22 hippocampal neurons,which can lead to its injury,and the injury effect is dose and time-dependent with propofol.Lncrna BDNF-as and BDNF are involved in the injury of hippocampal neurons induced by propofol.Down regulating the expression of LNC BDNF-as can protect hippocampal neurons damaged by propofol toxicity by up regulating BDNF.In the toxic injury model of HT22 hippocampal neurons induced by propofol,lncrna BDNF-as is involved in the injury of HT22 hippocampal neurons induced by propofol through BDNF-as / BDNF / Trk B pathway.