Altered small bowel propulsion associated with parasitism.

Experiments were designed to test the hypothesis that alterations of intestinal motility accompany enteric helminth infections. Motility was measured in rats during the intestinal phase of infection with the nematode Trichinella spiralis by following the transit of radioactive chromium through the gut. Intraduodenal catheters were surgically implanted in rats. One week after the operation one group of animals was infected with 8 x 10(3) T. spiralis larvae and a second group was infected with 16 x10(3) larvae. A third group of uninfected rats served as controls. Three, four, or five days postinfection, Na2 51CrO4 was injected through the catheter into the duodenum or fasted animals and its propulsion through the small bowel was allowed to progress for 15 min. The distribution of radioactivity throughout the small intestine and cecum was then plotted as a function of gut length. Intestinal transit was increased significantly by infection. The leading edge of radioactivity transversed 100% of the gut length in infected rats and 70% in controls. The amount of injected radioactivity transversing the midpoint of the small intestine was estimated by regression equations to be 38% of the injected dose for control rats and 59 and 57% for infected groups. Increased propulsive activity in parasitized rats was associated with inflammatory changes and a significant reduction in disaccharidase levels in the gut mucosa. The latter conditions were most marked in the proximal small bowel where the majority of worms resided.