The isolated bowel segment (Iowa model II) created in functioning bowel.

In experimental rats (n = 15), an isolated bowel segment (IBS) was created by (1) initial enteropexy between an 8-cm-long jejunal segment and the liver margin (hepatoenteropexy; Iowa model II) with its proximal and distal ends divided and immediately reanastomosed in an end-to-end fashion to reconstruct the bowel; and (2) secondary division of the IBS mesentery 5 weeks later. The IBS is then completely free of its mesentric and intramural nervous and vascular communications. The viability of the IBS is preserved by vascular collaterals developed at the hepatoenteropexy. Twelve rats proceeded to the second procedure, having tolerated regular rat chow with satisfactory weight gain. The Iowa model II created in functioning bowel was evaluated by contrast studies and myoelectrical activities. Contrast studies demonstrated peristalsis in the IBS. In the myoelectrical recordings, the frequency of slow wave was 32.5 +/- 1.0 in the IBS and 36.3 +/- 0.8 in the normal bowel (P less than .05). During fasting, the migrating motor complex (MMC) was observed to propagate aborally in the IBS in a coordinated fashion. The cyclic period of the MMC was 17.2 +/- 1.1 minutes in the IBS and 15.8 +/- 0.8 minutes in the normal bowel (P = .30). We conclude from this study that (1) the IBS (Iowa model II) retains motor function as demonstrated by successful feeding, as well as contrast studies and myoelectrical recordings that were essentially identical to those in the normal bowel; and (2) the IBS (Iowa model II) has significant research potential for studies of bowel physiology.