Background: Growth hormone (GH) improves net protein anabolism and stimulates wound healing. Although GH is also known to exert the trophic effect on the intestinal tract, its role in the healing of intestinal ulceration is not known. The aim of this study was to evaluate the effects of exogenous GH coinfused with parenteral nutrition (PN) in an experimental model of inflammatory bowel disease in rats.
Methods: All rats underwent central venous cannulation and were randomized to two groups after induction of small intestinal ulceration with indomethacin. Both groups received the same PN formula. In addition, the GH group (n = 10) received subcutaneous injections of human GH at a dose of 1.0 IU/kg daily for 4 days, whereas the control group (n = 10) received injections of normal saline solution. Nitrogen balance, macroscopic inflammation score, intestinal myeloperoxidase activity, DNA content, and mucosal permeability were determined for each rat. Insulin-like growth factor-I (IGF-I) mRNA was detected by reverse transcription and polymerase chain reaction.
Results: Administration of GH significantly improved the cumulative nitrogen balance, ameliorated the gross inflammation score, and decreased intestinal myeloperoxidase activity. Similarly, intestinal permeability was significantly decreased in the GH group as compared with the control group. GH treatment resulted in increased plasma concentration of IGF-I and IGF-I mRNA expressions in both the liver and the small intestine compared with those in the control group.
Conclusions: Exogenous GH plays an important role in accelerating intestinal healing in an experimental model of small bowel ulceration in rats. The mechanisms may include the stimulated IGF-I production, which thereafter augments intestinal epithelial cell growth.