Effects of different ischemic preconditioning strategies on physiological and cellular mechanisms of intestinal ischemia/reperfusion injury: Implication from an isolated perfused rat small intestine model.

Yuk Lung Wong,Norbert Weiler,Markus Steinfath,Martin Albrecht,Rene Rusch,Matthias Gruenewald,Karina Zitta,Thilo Wedel,François Cossais,Rouven Berndt,Lars Hummitzsch,Ingmar Lautenschläger

doi:10.1371/journal.pone.0256957

Abstract

BackgroundIntestinal ischemia/reperfusion (I/R)-injury often results in sepsis and organ failure and is of major importance in the clinic. A potential strategy to reduce I/R-injury is the application of ischemic preconditioning (IPC) during which repeated, brief episodes of I/R are applied. The aim of this study was to evaluate physiological and cellular effects of intestinal I/R-injury and to compare the influence of in-vivo IPC (iIPC) with ex-vivo IPC (eIPC), in which blood derived factors and nerval regulations are excluded.MethodsUsing an established perfused rat intestine model, effects of iIPC and eIPC on physiological as well as cellular mechanisms of I/R-injury (60 min hypoxia, 30 min reperfusion) were investigated. iIPC was applied by three reversible occlusions of the mesenteric artery in-vivo for 5 min followed by 5 min of reperfusion before isolating the small intestine, eIPC was induced by stopping the vascular perfusion ex-vivo 3 times for 5 min followed by 5 min of reperfusion after isolation of the intestine. Study groups (each N = 8–9 animals) were: iIPC, eIPC, I/R (iIPC group), I/R (eIPC group), iIPC+I/R, eIPC+I/R, no intervention/control (iIPC group), no intervention/control (eIPC group). Tissue morphology/damage, metabolic functions, fluid shifts and barrier permeability were evaluated. Cellular mechanisms were investigated using signaling arrays.ResultsI/R-injury decreased intestinal galactose uptake (iIPC group: p<0.001), increased vascular perfusion pressure (iIPC group: p<0.001; eIPC group: p<0.01) and attenuated venous flow (iIPC group: p<0.05) while lactate-to-pyruvate ratio (iIPC group, eIPC group: p<0.001), luminal flow (iIPC group: p<0.001; eIPC group: p<0.05), goblet cell ratio (iIPC group, eIPC group: p<0.001) and apoptosis (iIPC group, eIPC group: p<0.05) were all increased. Application of iIPC prior to I/R increased vascular galactose uptake (P<0.05) while eIPC had no significant impact on parameters of I/R-injury. On cellular level, I/R-injury resulted in a reduction of the phosphorylation of several MAPK signaling molecules. Application of iIPC prior to I/R increased phosphorylation of JNK2 and p38δ while eIPC enhanced CREB and GSK-3α/β phosphorylation.ConclusionIntestinal I/R-injury is associated with major physiological and cellular changes. However, the overall influence of the two different IPC strategies on the acute phase of intestinal I/R-injury is rather limited.

Highlights

Ischemia/reperfusion (I/R)-injury commonly results in organ failure and is associated with high mortality
Using an established perfused rat intestine model, effects of in-vivo IPC (iIPC) and ex-vivo IPC (eIPC) on physiological as well as cellular mechanisms of I/R-injury (60 min hypoxia, 30 min reperfusion) were investigated. iIPC was applied by three reversible occlusions of the mesenteric artery invivo for 5 min followed by 5 min of reperfusion before isolating the small intestine, eIPC was induced by stopping the vascular perfusion ex-vivo 3 times for 5 min followed by 5 min of reperfusion after isolation of the intestine
Effects of ischemic preconditioning on intestinal ischemia/reperfusion injury while lactate-to-pyruvate ratio, luminal flow, goblet cell ratio and apoptosis were all increased

Summary

Introduction

Ischemia/reperfusion (I/R)-injury commonly results in organ failure and is associated with high mortality. Reperfusion in ischemic organs like heart, brain kidney and intestine increases the initial tissue damage leading to so called I/R-injury [1,2]. Intestinal I/R-injury often results in impaired epithelial/endothelial barrier function, reduced bowel movement and malabsorption leading to intestinal bacterial translocation with an increased risk for sepsis and organ failure [3,4]. Some recent studies implicate ameliorated intestinal damage by remote ischemic preconditioning (RIPC) [5,6], no clinically established therapy options are available so far to reduce intestinal I/R-injury. Intestinal ischemia/reperfusion (I/R)-injury often results in sepsis and organ failure and is of major importance in the clinic. The aim of this study was to evaluate physiological and cellular effects of intestinal I/R-injury and to compare the influence of in-vivo IPC (iIPC) with ex-vivo IPC (eIPC), in which blood derived factors and nerval regulations are excluded

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