Effects of denervation at ileocecal junction and ileocecal resection in dogs


Address for Correspondence
Hiroki Morita, Department of General Surgical Science (Surgery 1), Gunma University School of Medicine, 3-39-22 Showamachi, Maebashi, Gunma 371-8511, Japan.
Tel: +81 27 220 8224; fax: +81 27 220 8230;
e-mail: m09702031@gunma-u.ac.jp


Background  To investigate neural regulation at the ileocecal junction (ICJ) and motility changes after ileocecal resection (ICR). Previous studies showed normal basal motility at the ICJ directly by force transducers in dogs, but these observations were limited to normal contractile activity.

Methods  Continuous strain gauge recordings of stomach, terminal ileum, ileocecal sphincter (ICS), and colon were performed in dogs. The dogs were divided into four groups, namely control (CONT), extrinsic denervation at ICJ (ED), intrinsic denervation at ICJ (ID), and ICR groups. Colonic activity was recorded 2 h before a meal, in the early postprandial period (first 2 h), and in the late postprandial period (4–6 h after a meal). The meal lasted 5 min.

Key Results  Motility index was significantly increased at the ICS (= 0.0056) and proximal colon (= 0.0059) after feeding. However, such changes were not observed in the ED and ID groups. The amplitude of contractions at proximal colon in the interdigestive state was significantly decreased by ED. In the ID and ICR groups, the numbers of nonmigrating contractions were significantly decreased (< 0.05), and colonic migrating motor complex (CMMC) ratio was significantly higher than that of the CONT group (< 0.001). The dogs in these two groups had diarrhea.

Conclusions & Inferences  Gastrocolonic response at the ICJ may require both intrinsic and extrinsic innervation. When ID was performed, CMMC ratio increased. As a result, intraluminal water absorption may have decreased. ID may be one of the causes of diarrhea after ICR.