Intestinal hypertrophy after small intestinal bypass in the rat. Studies on methods and reversibility of changes

A jejuno-ileostomy was created in rats, bupassing 85--90% of the small intestine, by means of a self-emptying blind loop. Control animals were subjected to laparotomy and suture-making of vie intestinal segments. At the end of the experiments, intestinal wet and dry weight and villus height were determined in the five different segments of the small intestine taken from both experimental and control animals. After 2 weeks, a significant hypertrophy occurred in the functioning part of the small intestine of the shunt-operated animals, while an atrophy occurred in the blind loop. In a shunt-operated group of animals, the normal anatomy was re-established after 2 weeks and the animals were sacrificed 4 weeks later and compared with (a) control animals, (b) shunt-operated animals. In the re-operated animals, the hypertrophic changes disappeared and, except for the increased wet weight of one jejunal and one ileal segment (p less than 0.05), there were no significant differences in comparison with the control animals. The villus height did not differ significantly from that of the control animals, except for the second jejunal segment, whicntestine of the rat, developing during the 2 weeks after establishment of a jejuno-ileal bypass, are reversible within 4 weeks.