Effects of peritoneal injury and endotoxin on myoelectric activity and transit.

Background: The combined effects of peritoneal injury and intraabdominal infection on gastrointestinal motility in postoperative ileus are poorly understood

Materials And Methods: Sprague Dawley rats underwent placement of three electrodes on the small intestine and a tube gastrostomy. Animals were divided into four groups: a control (n = 12), a peritoneal injury (PI, n = 12), a peritoneal injection of lipopolysaccharide (LPS, n = 12), and a LPS + PI group (n = 12). After myoelectric activity recording on postoperative day (POD) 1, half of the rats in each group underwent intestinal transit studies. The remainder of the rats underwent another myoelectric activity recording as well as intestinal transit study at 48 h after operation

Results: Although six to eight of rats in the control, PI, and LPS groups recovered migrating myoelectric complex (MMC) on POD 1, no rats in the LPS + PI group recovered MMC by POD 1. The transit distance on POD 1 in the PI (36 +/- 2.5 cm) and LPS + PI group (38 +/- 2.8 cm) was shorter than that in the control group (53 +/- 2.0 cm, P < 0.05)

Conclusions: Full recovery of liquid intestinal transit precedes the return of MMC activity after abdominal surgery in the rats. Peritoneal injury causes decreased intestinal transit and when combined with intraabdominal injection of LPS may cause the delayed recovery of MMC activity.