Gastric stapling for morbid obesity: gastrointestinal response in a rat model

The adaptive response of the gastrointestinal tract to gastric stapling was studied in a Zucker (fafa) genetically obese rat model. The effects of gastric stapling in rats with a Roux-en-Y gastrojejunostomy were compared to Roux-en-Y and intact controls. Rats (225 to 275 g) were divided into three groups: group I (GI), Roux-en-Y, stapled, ad libitum fed; group II, Roux-en-Y, unstapled; and group III, intact (laparotomy only). Groups II and III were further subdivided into group IIA (GIIA) and group IIIA (GIIIA), pair-fed to GI; and group IIB (GIIB) and Group IIIB (GIIIB), fed ad libitum. All rats were fed a diet of liquid rat formula and rat food (50:50 cal ratio). After 2 wk rats were killed and the liver, pancreas, and stomach removed, weighed, and tissue taken for histology. The intestine was divided into three segments corresponding to the excluded segment (1, duodenum), transposed segment (2, jejunum), and ileal segment (3), with tissue taken for histology. Liver lipid, pancreatic amylase, serum amylase and gastrin, and intestinal mucosal protein and DNA were measured. Weight gain, g/14 days, was: GI, 24.1 +/- 7.8; GIIA, 17.0 +/- 2.0; GIIB, 42.6 +/- 4.8; GIIIA, 17.6 +/- 4.7; GIIIB, 54.6 +/- 8.9. All rats were in positive N balance. Liver weight and lipid were similar in all groups. Pancreatic mass was significantly increased in all Roux-en-Y animals, while amylase activity per g tissue was significantly less than in intact animals. Stapled rats had atrophy of the glandular portion of the stomach, decreased stomach mucosal weight, and lower serum gastrin concentration compared with all other rats (p less than 0.01). In stapled rats, segment weight and mucosal weight were lower in the excluded segment, and higher in the transposed segment, compared to all other rats. Tissue pathology was found only in stapled rats: gastric atrophy, focal fibrosis of gastric wall, peritonitis, minimal to mild multifocal hepatitis, and mild periductal fibrosis of the pancreas. There are significant early adaptive and pathological changes after gastric stapling in the rat.