Transcriptomic Analysis of the Effect of Remote Ischaemic Conditioning in an Animal Model of Necrotising Enterocolitis

Abstract

AbstractBackground and AimsPreviously, we reported that remote ischaemic conditioning (RIC) reduces bowel injury in an animal model of Necrotising enterocolitis (NEC). We investigated the mechanisms by which RIC confers this protective effect using RNA-Seq.MethodsRelated rat-pups were randomly assigned to four groups: SHAM, intestinal ischaemia-reperfusion injury (IRI), RIC and RIC+IRI. Anaeasthetised IRI animals underwent 40 minutes of intestinal ischaemia, followed by 90 minutes of reperfusion. Animals that underwent RIC had three 5 minute cycles of alternating ischaemia/reperfusion by ligature application to the hind limb.Illumina NextSeq 550 High Throughput NG Sequencing and genome alignment was performed with Qiagen’s CLC read mapper to produce raw gene counts. Transcriptome analysis was done usingRv 3.6.1.ResultsDifferential expression testing showed 868 differentially expressed genes, in animals exposed to RIC alone compared to SHAM, 135 differentially expressed with IRI/RIC compared to IRI alone. Comparison between these two sets showed 25 genes were differentially expressed in both groups. Of these, several genes involved in pro-inflammatory pathways, including NF-ĸβ2, Cxcl1, SOD2 and Map3k8, all showed reduced expression in response to RIC. Targeted analysis revealed increased expression in PI3K which is part of the RISK-pathway identified as a response to RIC in cardiac tissue.ConclusionsExpression patterns suggest that within the intestine, RIC suppresses pro-inflammatory pathways and that an equivalent of the RISK-pathway may be present in the intestine. The cross-over between the pro-inflammatory pathways suppressed here and those that are involved in several stages of the pathogenesis of NEC, further support the potential for RIC as a treatment for NEC.