Bioinformatics Analysis Of Key Genes And MiRNAs In The Treatment Of Spinal Cord Ischemia-reperfusion Injury With BMSCs Combined With BDNF

Spinal cord ischemia-reperfusion injury（SCII）is a pathological process in which various pathogenic factors leading to spinal cord ischemia and hypoxia are alleviated,and the blood supply of the spinal cord is restored,and its neurological function cannot be recovered and may be further deteriorated than the original level.SCII can lead to different degrees of neurological impairment,including paraplegia,lower limb paralysis,sexual dysfunction,and organ dysfunction（such as bladder and intestine）,which seriously endangers the life,health,and quality of life of patients.Bioinformatics is an interdisciplinary subject that uses applied mathematics,informatics,statistics,and computer science to study biology.Common uses of bioinformatics include identifying candidate genes and nucleotides,genome annotation,gene and protein expression analysis,regulatory analysis,and so on.Studies have shown that bone marrow mesenchymal stem cells（BMSCs）can repair nerve cells and promote axon regeneration by secreting neurotrophic factors,thus improving the function after spinal cord injury.The transplanted BMSCs can secrete a variety of neurotrophic factors and exogenous neurotrophic factors to work together to play a neuroprotective role.Brain-derived neurotrophic factor（BDNF）is a member of a highly conservative and soluble protein family in mammals that plays a key role in the development of the nervous system in adults.Objective:Based on bioinformatics,this study is to study the key genes and miRNAs of the protective effect of BMSCs combined with BDNF on SCII.The gene chips used for bioinformatics analysis are all from our research group.The R is used to analyze the differential genes and their corresponding miRNAs,and its GO function and KEGG pathway are enriched and analyzed.Finally,the finally obtained differential genes and their corresponding miRNAs are verified by real-time quantitative PCR（RT-PCR）.Methods:Rats were randomly divided into 5 groups: Sham group,SCII group,Cell group,Empty plasmid group,and BDNF group.The SCII model was established and the BMSCs of SD（Sprague Dawley）rats were extracted.The extracted BMSCs were subjected to culture,surface markers,and cycle identification for subsequent experiments.In the Cell group,bone marrow mesenchymal stem cells were injected through the retrobulbar vein of rats.Group Empty plasmid was injected into BMSCs infected with empty vector lentivirus,BMSCs infected with BDNF vector lentivirus were injected into the BDNF group.The r language is used to analyze the differential genes and their corresponding miRNAs in these five groups of gene chip data,to obtain the heat map of the differential genes and their corresponding miRNAs,and the volcano map of up-regulation and down-regulation of each two groups of genes.Then,the GO function and KEGG pathway are enriched and analyzed,and the bubble diagram of GO function and KEGG signal pathway is made.Use Cytospace software to make a network diagram of differential genes and their corresponding miRNA.Finally,realtime quantitative PCR（RT-PCR）was used to verify the finally obtained differential genes and their corresponding miRNA,and a histogram of differential expression was made.Results:（1）There were 803 differential genes in the sham operation group,model group,cell therapy group,empty vector group,and BDNF group.（2）Compared with the sham group,384 genes were up-regulated and 351 genes were down-regulated in the model group;Compared with the model group,322 genes were up-regulated and 331 genes were down-regulated in the cell therapy group.Compared with the model group,431 genes were up-regulated and 353 genes were down-regulated in BDNF combined with the cell therapy group.Compared with the cell therapy group,BDNF combined with the cell therapy group has 371 genes up-regulated and 480 genes down-regulated.（3）GO enrichment analysis of differential genes: In terms of biological process（BP）,differential genes are mainly enriched in the positive regulation of catabolism,the positive regulation of protein catabolism,gene processing,etc.In terms of cell component（CC）,the differential genes are enriched in the splice body complex,endosome,and U2-type splice body complex.In terms of molecular function（MF）,zinc ion transmembrane transporter activity,divalent inorganic cation transmembrane transporter activity,ubiquitin-like protein ligase binding,etc.（4）The enrichment analysis of the KEGG pathway of differential genes mainly includes the interleukin-17 signaling pathway,fat digestion and absorption,glutathione metabolism,and so on.（5）There are two groups of differential genes and miRNA targeted by them,namely Btg2 and mi R-337-5p,Fosl2 and mi R-19b-3p.There are significant differences between the two genes,but there is no significant difference in micro RNA targeted by them,namely Egr1 and Serpine1.Conclusion:1.Compared with the model group,the BDNF combined with the BMSCs treatment group had two sets of differential genes and their targeted miRNAs,which were Btg2 and mi R-337-5p,Fosl2 and mi R-19b-3p,respectively;2.The efficacy of BMSCs combined with BDNF in the treatment of SCII is more significant than that of BMSCs alone;3.Immune and inflammatory responses play an important role in the development of SCII.