title: Longitudinal mechanical tension induces growth in the small bowel of juvenile rats.
abstract: BACKGROUND
  The aim of our study was to apply longitudinal force to the small bowel to increase the length of intestine in juvenile rats.
  
  
  METHODS
  Fifty juvenile rats had double barrelled, blind loop ostomies created using an isolated segment of bowel. Our intestinal lengthening device was inserted into one of the loops and the second loop served as a control. Once the device was deployed, the experimental, control, and in situ segments of bowel were evaluated for length, weight, histology, and disaccharidase enzyme activity.
  
  
  RESULTS
  Mechanical tension increased intestinal length by 149%. The lengthened bowel also exhibited a greater total weight (218%), greater mucosal weight (122%), and increased protein mass (164%) compared with the control limb of bowel. Histologically, there was a markedly increased thickness of the muscularis propria in the lengthened bowel (200% increase compared with the control limb). Functionally, we found increased total disaccharidase activity in the lengthened bowel (between 47% and 350%, depending on the particular enzyme tested; p<0.01).
  
  
  CONCLUSIONS
  Mechanical tension induces intestinal growth by increasing length, weight of the bowel and mucosa, and protein mass. Histological changes, such as increases in Paneth cells, suggest that increased proliferation and reorganisation of the mucosa and muscularis propria are a response to mechanical tension. Functionally, increased intestinal length corresponds with increased disaccharidase activity, thus implying potential increased absorptive capacity of the lengthened bowel.
authors.affiliation: Department of Surgery, Division of Pediatric Surgery, PO Box 31295, Duke University Medical Center, Durham, NC 27710, USA. saffo001@mc.duke.edu
authors.forename: S D
authors.initials: SD
authors.lastname: Safford
authors.forename: A J
authors.initials: AJ
authors.lastname: Freemerman
authors.forename: K M
authors.initials: KM
authors.lastname: Safford
authors.forename: R
authors.initials: R
authors.lastname: Bentley
authors.forename: M A
authors.initials: MA
authors.lastname: Skinner
mesh_terms: D000818:Animals; D007413:Intestinal Mucosa / Q000201:enzymology / Q000502:physiology; D007421:Intestine, Small / Q000033:anatomy & histology / Q000201:enzymology / Q000254:growth & development*; D008297:Male; D009929:Organ Size / Q000502:physiology; D011506:Proteins / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D013314:Stress, Mechanical
chemical_list: D011506:Proteins