Tyrphostin AG 126 inhibits development of postoperative ileus induced by surgical manipulation of murine colon

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Abstract
Manipulation of the bowel during abdominal surgery leads to a period of ileus, which is most severely manifested after procedures that directly involve the colon. Ileus is associated with the increased expression of proinflammatory cytokines and chemokines, a leukocytic infiltration into the muscularis, and the release of mediators from resident and infiltrating leukocytes that directly inhibit intestinal smooth muscle contractility. Phosphorylation of tyrosine residues on regulatory proteins by protein tyrosine kinases (PTKs) occurs at multiple steps in the signaling cascades that regulate the expression of proinflammatory genes. The purpose of this study was to determine whether inhibition of PTK activity will attenuate the inflammatory response associated with colonic ileus and lead to improved function. Using a rodent model of colonic postoperative ileus, we demonstrate that a single bolus injection of the PTK inhibitor tyrphostin AG 126 (15 mg/kg sc) before surgery significantly attenuates the surgically induced impairment of colonic contractility both in vivo and in vitro. Improvement in function was associated with a reduction in magnitude of inflammatory cell infiltrate and with a decrease in transcription of genes encoding proinflammatory mediators IL-1β and monocyte chemoattractant protein (MCP)-1, inducible nitric oxide synthase, and cyclooxygenase-2. Furthermore, tyrphostin AG 126 pretreatment significantly inhibited activation of multifactorial transcription factor NF-κB, which could form the basis for reduction in proinflammatory mediator expression. These data demonstrate for the first time that inhibition of PTK activity may represent a novel approach for management of ileus in the clinical setting.