Increased expression of insulin-like growth factor in intestinal lengthening by mechanical force in rats

J Pediatr Surg. 2007 Dec;42(12):2057-61. doi: 10.1016/j.jpedsurg.2007.08.027.


Introduction: A segment of the jejunum could double its length by the application of an axial mechanical force. We hypothesize that this growth is correlated with an increased expression of insulin-like growth factor (IGF-I) in the jejunum.

Methods: Adult Sprague-Dawley rats underwent the isolation of a 1.5-cm segment of the jejunum. The isolated jejunal segment was either lengthened using mechanical force or left alone for 3 weeks. The jejunal segments were analyzed by quantitative polymerase chain reaction and immunofluorescence for the expression of IGF-I.

Results: Whereas jejunal segments that underwent isolation alone did not change their length, isolated jejunal segments that were stretched by applying a gradual mechanical force doubled their initial length. Both groups increased their muscular thickness 5 folds as compared to the normal jejunum. The mRNA level of IGF-I in the lengthened jejunum was 6 folds higher than that in the normal jejunum, but the IGF-I mRNA level in the isolated jejunum without mechanical lengthening was unchanged. By immunofluorescence, the increased IGF-I expression in the lengthened jejunum was localized to the intestinal smooth muscle cells.

Conclusions: Insulin-like growth factor I may be an important signal induced by the applied axial force that mediates longitudinal intestinal growth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Female
  • Fluorescent Antibody Technique
  • Jejunum / growth & development*
  • Jejunum / pathology
  • Jejunum / surgery
  • Models, Animal
  • Muscle, Smooth / growth & development
  • Muscle, Smooth / pathology
  • Organ Size
  • Probability
  • RNA, Messenger / analysis
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Sensitivity and Specificity
  • Somatomedins / analysis*
  • Stress, Mechanical
  • Tissue Expansion / methods*


  • RNA, Messenger
  • Somatomedins