Remote Ischaemic Pre-Conditioning Reduces Intestinal Ischaemia Reperfusion Injury in a Newborn Rat

Abstract

ObjectiveRemote ischaemic conditioning (RIC) has been shown to reduce ischaemia-reperfusion injury(IRI) in multiple organ systems. IRI is seen in multiple bowel pathologies in the newborn, including NEC. We investigated the potential of RIC as a novel therapy for various intestinal pathologies in the newborn. MethodsWe used an established intestinal IRI model in rat pups which results in similar intestinal injury to necrotising enterocolitis (NEC). Animals were randomly allocated to IRI only(n = 14), IRI + RIC(n = 13) or sham laparotomy(n = 10). The macroscopic extent of intestinal injury is reported as a percentage of total small bowel. Injury severity was measured using Chiu-Park scoring. Neutrophil infiltration/activation was assayed by myeloperoxidase activity. Immunohistochemistry was used to assess the expression of hypoxia-inducible factor alpha (HIF-1α). Data are median (interquartile range). ResultsAnimals that underwent RIC showed a decreased extent of macroscopic injury from 100%(85–100%) in the IRI only group to 58%(15–84%, p = 0.003) in the IRI + RIC group. Microscopic injury score was significantly lower in animals that underwent RIC compared to IRI alone (3.5[1.25–5] vs 5.5[4–6], p = 0.014). Intestinal myeloperoxidase activity in animals exposed to IRI was 3.4 mU/mg of tissue (2.5–3.7) and 2.1 mU/mg(1.5–2.8) in the IRI + RIC group(p = 0.047). HIF-1α expression showed a non-significant trend towards reduced expression in the IRI + RIC group. ConclusionsRIC reduces the extent and severity of bowel injury in this animal model, supporting the hypothesis that RIC has therapeutic potential for intestinal diseases in the newborn.