Effects of small bowel exclusion on intestinal myoelectrical activity pattern: comparison between innervated and denervated (transplanted) Thiry-Vella loops in rats

Small bowel transplantation (SBT) leads to several changes in normal intest inal physiology with special reference to lymphatic disruption and graft de nervation. Intestinal myoelectrical activity (MA) has been studied in diffe rent conditions, but little is known about MA in excluded bowel segments wi thout the influence of nutrients. We performed this study to evaluate the e ffects of bowel exclusion on MA pattern. Fifteen Wistar rats were divided i nto two groups: five were used as donors and five as recipients for SET; th e remaining five underwent isolation of a jejunal segment as Thiry-Vella lo op (TVL). On the 20th postoperative day, four bipolar electrodes were impla nted in the small bowel of each rat: proximally and distally on the transpl anted and the native intestine (SBT group); proximally and distally on the TVL and across the jejunal anastomosis (TVL group). On the 30th postoperati ve day, MA was recorded for 30 min after a 12 h fast. MA pattern was not al tered by the exclusion of inervated jejunal segments (TVLs) with maintenanc e of high amplitude and migrating myoelectric complex (MMC) occurrence inde pendent of MA in the continuity bowel. The characteristic regular spiking a ctivity was not observed in transplanted grafts and MA analysis showed slow waves containing superimposed irregular spiking activity.