Predisposition to colonic dysplasia is unaffected by continuous administration of insulin-like growth factor-I for twenty weeks in a rat model of chronic inflammatory bowel disease

Background Insulin-like growth factor-I (IGF-I) is currently under evaluati on for the treatment of a variety of chronic disease conditions. We investi gated the safety of long-term IGF-I administration in a rat model of inflam matory bowel disease which predisposes to the development of dysplasia, Methods Chronic consumption of dextran sulphate sodium (DSS) by rats manife sts a colitis with dysplastic features. Rats consumed 2% DSS for 4 weeks wh en pumps were implanted to deliver either vehicle or IGF-I for 15 or 20 wee ks while rats continued to consume DSS. Features of colitis and dysplasia w ere assessed at kill. Results Compared to vehicle, 20 weeks IGF-I significantly increased body we ight by 19% and total gut weight by 43%, Colonic crypt depth, proliferative compartment, labelling index, dysplasia, neoplasia and other indices of co litis were not significantly affected. Conclusions Twenty weeks administration of IGF-I to rats induced growth of the intestine but did not affect the severity of experimentally-induced col itis or the incidence or progression of colonic dysplasia.