EFFECTS OF INSULIN-LIKE GROWTH-FACTOR-I ADMINISTRATION ON RADIATION ENTERITIS IN RATS

Background: Acute radiation-induced damage to the small bowel occurs f requently during abdominal radiotherapy. Since the small intestine is selectively responsive to the growth-promoting effects of insulin-like growth factor-I (IGF-I), we investigated the effects of IGF-I adminis tration on mucosal recovery from radiation enteritis in the rat. Metho ds: Rats received a single 10-Gy dose of total abdominal irradiation f ollowed by implantation of mini-pumps infusing either IGF-I or vehicle for 4 days. After the rats had been killed, gut organs were weighed b efore light microscopic and biochemical examination Results: Irradiate d rats receiving IGF-I lost less body weight than vehicle-treated rats , whereas the wet weights of the stomach, small intestine, and colon w ere increased by 10%, 19%, and 21%, respectively, and crypt depth was increased in the duodenum, jejunum, and ileum. Conclusions: IGF-I admi nistration after abdominal irradiation increased small-intestinal mass and improved indicators of mucosal integrity, suggesting acceleration of small-intestinal mucosal recovery from radiation injury.