The effect of growth hormone on the bursting strength of ileal anastomotic segments in radiation-injured rat bowel

The potential for postoperative complications in irradiated intestinal anastomoses is well known. There has been limited evaluation of factors that may improve wound healing in radiation-injured bowel. Growth hormone (GH) has been shown to improve wound healing. In animal models GH has been demonstrated to increase strength of large bowel anastomoses in nonirradiated bowel. The purpose of this study was to evaluate, in a rat model, the effect of GH on the bursting pressure of radiation-injured terminal ileal anastomoses in a rat model. Fifty-four rats were treated with 1700 cGy of pelvic irradiation in a single dose. Seventeen weeks later resection of a segment of terminal ileum and an ileo-ileostomy was performed. Half the rats received GH (2.0 mg/kg/day) and the rest received normal saline subcutaneously for 7 days starting on the day of surgery. On the seventh postoperative day the anastomosis site was identified at reoperation and bursting pressure was measured in vivo. A significantly greater bursting pressure was observed in the GH-treated rats compared to the control group (208.9 ± 27 cm H₂O vs 177 ± 53 cm H₂O, P < 0.025). GH treatment resulted in an 18% greater strength of radiation-injured terminal ileal anastomotic segments, as measured by bursting pressure. These findings suggest a possible role for GH in decreasing the morbidity in patients who undergo intestinal surgery after radiation treatment.