Impact of different surgical traumas on postoperative ileus in rats and the mechanisms involved.

The degree of postoperative ileus and the underlying pathophysiological mechanism among different types of surgical traumas have not been examined. The aim of this study was to investigate the inflammatory and oxidative stress changes in rat intestinal muscularis and gastrointestinal transit among three types of surgical traumas. Rats were randomized assigned to four groups: control group, intestinal manipulation (IM) group, intestinal ischemia/reperfusion injury (IR) group and peritoneal air exposure (AE) group. Gastrointestinal transit was measured 24 hours after surgery. Malondialdehyde (MDA), glutathione (GSH) and inflammatory mediators in intestinal muscularis were measured. Influx of neutrophil in intestinal muscularis was also determined. The degree of gastrointestinal motility impairment was equal between the IM and AE groups. However, the IR group was subject to a less impairment of gastrointestinal motility compared with the IM and AE groups. The IM group showed the most significant increase of inflammatory response, while the AE group showed the most significant increase of oxidative stress. The IR group showed a moderate increase of inflammatory response and oxidative stress. Rats subjected to IM, IR and AE could all develop into POI. We speculate that oxidative stress should be an equally important pathophysiological mechanism of POI as inflammation.