Background: Postoperative adhesions can cause serious complications after abdominal surgery. This study demonstrates the role of the cholinergic nervous system in the development of postoperative intestinal adhesion.
Methods: Postoperative intestinal adhesion was induced by sprinkling talc on the small intestines of rats, and the adhesion rate, histology, and gastrointestinal transit were evaluated. To investigate the involvement of the cholinergic nervous system in postoperative intestinal adhesion, we evaluated choline acetyltransferase (ChAT) activity, muscarinic receptor density, and the preventive effect of a muscarine receptor agonist, bethanechol, on talc-induced intestinal adhesion in rats.
Results: Histologic examination revealed inflammation in the intestinal adhesion regions, but no damage was seen in sham-operated rats. The rate of adhesion formation had significantly increased 3-7 days after surgery. The gastrointestinal transit was decreased by about 30% in the talc-induced intestinal adhesion rats. ChAT activity decreased by about 50% in adhesion regions. In contrast, the density of muscarinic receptors was higher in rats with talc-induced intestinal adhesions. Furthermore, bethanechol significantly prevented 30%-41% of adhesion formation in rats with talc-induced intestinal adhesions. This action was inhibited by subcutaneous injection of atropine.
Conclusions: Postoperative intestinal adhesion affected the cholinergic nervous system as demonstrated by decreased ChAT activity and increased density of muscarinic receptors. These alterations of gastrointestinal function might be a cause of adhesion formation.