Colonic postoperative inflammatory ileus in the rat.

Area of Science:

• Gastroenterology
• Surgical Inflammation
• Gastrointestinal Motility

Background:

• Postoperative ileus (POI) is a common complication after abdominal surgery.
• Inflammation of the intestinal muscularis is a proposed mechanism for POI.
• The role of colonic manipulation in POI remains largely uninvestigated.

Purpose of the Study:

• To investigate local inflammatory events in the colonic muscularis as a cause of POI.
• To determine if colonic manipulation induces inflammation and smooth muscle dysfunction.
• To assess the potential therapeutic role of inhibiting inflammatory mediators.

Main Methods:

• Rats underwent colonic manipulation, with subsequent assessment of in vivo transit and motility.
• Leukocyte extravasation and inflammatory mediator mRNA expression were analyzed.
• In vitro circular muscle contractility was measured, and the effects of iNOS and COX-2 inhibition were evaluated.

Main Results:

• Colonic manipulation triggered significant leukocyte recruitment and increased inflammatory mRNA expression.
• A marked impairment of in vivo motor function and a 56% inhibition of in vitro smooth muscle contractility were observed.
• Inhibition of inducible nitric oxide synthase (iNOS) with L-NIL, but not cyclooxygenase-2 (COX-2) with DFU, ameliorated smooth muscle dysfunction.

Conclusions:

• Surgical manipulation of the colon initiates a local inflammatory cascade within the muscularis.
• This inflammatory response directly mediates smooth muscle dysfunction, contributing to postoperative ileus.
• Targeting iNOS may be a potential therapeutic strategy for preventing or treating POI.