OBJECTIVE
Intestinal manipulation triggers an inflammatory cascade within the muscularis causing postoperative ileus (POI). The aim of this study was to investigate the recovery and therapeutic potential of interleukin 10 (<em>IL1</em>0) for POI.
METHODS
POI was induced by bowel surgical manipulation (SM) in wild-type, <em>IL1</em>0(-/-) and recombinant murine <em>IL1</em>0 (rm<em>IL1</em>0)-treated mice. Immunohistochemistry localised <em>IL1</em>0 in the muscularis externa, histochemistry quantified neutrophil recruitment, and quantitative PCR quantified alterations in mRNA. Luminex multiplex analysis, Griess reaction and ELISA measured proteins, nitric oxide (NO) and prostanoid release from the muscularis externa, respectively, in 24 h organ culture. Gastrointestinal transit and jejunal circular muscle organ bath techniques assessed gastrointestinal function.
RESULTS
In <em>IL1</em>0 knockouts compared with the wild type, the expression of numerous proinflammatory mRNAs (IL6, <em>IL1</em> <em>beta</em>, chemokine C-C motif ligand 2 (CCL2) and haem oxygenase-1) and proteins (IL6, <em>IL1</em> alpha, <em>IL1</em>2, <em>IL1</em>7, interferon gamma, tumour necrosis factor alpha, CCL2, interferon-inducible protein-10 and granulocyte-macrophage colony-stimulating factor (GM-CSF)) were accentuated, and release of muscle inhibitors NO and prostanoids was increased; motility never recovered from manipulation and mortality rate was 87.5%. In wild types, complete functional recovery occurred in 7 days with no mortality. SM delay in transit and suppression in jejunal circular muscle contractions were significantly improved by rm<em>IL1</em>0 treatment. Upregulation in <em>IL1</em> <em>beta</em>, IL6 and CCL2 mRNAs and inflammatory mediators (<em>IL1</em> alpha, IL6, CCL2, macrophage inflammatory protein-1 alpha, GM-CSF, NO and prostaglandin) after SM were significantly less with rm<em>IL1</em>0 treatment, which resulted in a decrease in neutrophil recruitment compared with SM controls.
CONCLUSIONS
<em>IL1</em>0 plays an obligatory role in postoperative intestinal recovery, and exogenous <em>IL1</em>0 prevents its development. Pre-emptive exogenous recombinant human <em>IL1</em>0 could be a treatment for the prevention of clinical POI.