Insulin-like growth factor-I partially attenuates colonic damage in rats with experimental colitis induced by oral dextran sulphate sodium.
BACKGROUND
Administration of insulin-like growth factor-I (IGF-I) results in selective growth of the gastrointestinal tract. We investigated the effects of IGF-I on the colonic damage induced by oral dextran sulphate sodium (DSS) in the rat.


METHODS
Rats consumed 2% DSS in the drinking water for 10 days to induce colitis. Pumps were implanted on day 3 to deliver IGF-I for 7 days. Colonic histopathology and immunolocalization of transforming growth factor-beta1 (TGF-beta1) were assessed on day 10.


RESULTS
Compared with the colon of vehicle-treated rats consuming DSS, IGF-I increased the numbers of goblet cells by 76%, reduced the proportion of lamina propria cells expressing TGF-beta1, and reduced the thickness of submucosal and muscularis externa layers by 26% and 20%, respectively.


CONCLUSIONS
We conclude that the effects of IGF-I treatment on the colonic epithelium may be mediated directly, whereas the reduced inflammation in the mucosa and submucosa may be mediated by a mechanism other than up-regulation of TGF-beta1-mediated immunosuppression.
Howarth
G S
GS
Cooperative Research Centre for Tissue Growth and Repair and Child Health Research Institute, North Adelaide, South Australia.
Xian
C J
CJ
Read
L C
LC
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003093:Colitis, Ulcerative / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D003106:Colon / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D016264:Dextran Sulfate / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D016212:Transforming Growth Factor beta / Q000378:metabolism
D016212:Transforming Growth Factor beta; D007334:Insulin-Like Growth Factor I; D016264:Dextran Sulfate