INTESTINAL ADAPTATION FOLLOWING MASSIVE SMALL-BOWEL RESECTION IN THE MOUSE

BACKGROUND: Transgenic mice represent powerful tools for studying the role of genes and their expression under multiple conditions, and they may provide a unique model for studies of intestinal adaptation after massive small bowel resection (SBR). This study characterized a succe ssful model for SBR and intestinal adaptation in the mouse. STUDY DESI GN: Sham operation (bowel transection with reanastomosis) or SBR was p erformed on male C57BL/6 mice. A solid or liquid diet, various sizes o f monofilament suture for the anastomosis, and resection of 50 or 75 p ercent of the proximal small intestine were studied. In other studies, intestinal adaptation was characterized as changes in intestinal wet weight, DNA, protein, villus height, crypt depth, and crypt cell proli feration rates at 12 hours, 24 hours, three days, and one, two, and fo ur weeks after 50 percent SBR. RESULTS: Survival was significantly imp roved with a liquid diet (8 percent compared with 88 percent; p<.001) and modestly improved by using the smallest suture for anastomosis (60 percent for 7-0 compared with 88 percent for 9-0; p=not significant). Mice did not tolerate more than 50 percent SBR (16 percent survival r ate for 75 percent SBR compared with 85 percent survival rate for 50 p ercent SBR; p<.01). Small bowel resection augmented deal wet weight, D NA and protein content, villus height, crypt depth, and crypt-cell pro liferation rates.CONCLUSIONS: Provision of a liquid diet, using a smal l suture for anastomosis, and resection of no more than 50 percent of the proximal small intestine are important for survival. This model wi ll permit researchers using transgenic mice to better understand criti cal genes during intestinal adaptation after SBR.