Background and Goal of Study: In patients with postoperative ileus the colon is the last section of the gastrointestinal tract to return to normal function (1). Assessment of small bowel function in vitro and the evaluation of drug effects on small bowel function is golden standard (2). Up to now no reliable setting for the assessment of colonic function was available. Therefore our aim was to develop an experimental setting that allows the evaluation of colonic transit time in vitro, as well as the assessment of drug effects on colonic function.
Materials and Methods: Guinea pigs were sacrificed and their colon excised. Colonic segments (length 8 cm) were fixed on a polyacrylic tray filled with Tyrode's solution. After a resting period of 10 minutes the transit time of a wooden pellet was evaluated. In a first step we used different segments from all parts of the colon in order to evaluate their propulsive function. In a second step we assessed the number of stable transits in the propulsive segments.
Results and Discussions: Propulsive motility was found in the distal part of the colon. The occurrence of propulsive motility was connected with a change of colonic contents - it changed from fluid to compact. The figure below shows the number of possible transits in one segment. In the period between transit 3-8 the segments propulsive motility was relatively stable (transit time 1.14 ± 0.03 mm/sec), after that it decreased rapidly.
Conclusion(s): This new experimental setting is a reliable method to evaluate colonic motility in vitro. The period between transit 3-8 would be the ideal period to assess the effect of drugs on colonic motility.
1 Holte K. Br. J Surg 2000; 87: 148.
2 Holzer P. Altern Lab Animals 2003; 31: 419.