Recombinant growth hormone's effects on the strength and thickness of radiation-injured ileal anastomoses: A rat model

Background. Small bowel resections following radiotherapy for gynecologic cancers have resulted in significant rates of morbidity and mortality. The objective of this study was to evaluate the effect of rGH on the breaking strength and thickness of radiation-injured ileal anastomoses in an animal model. Materials and methods. Sprague-Dawley rats were treated with 1800 cGy of pelvic irradiation in a single fractionation. Seventeen weeks following pelvic teletherapy an ileo-ileostomy was performed. The rats were randomized to receive 2.0 mg/kg/day of rGH for 7 days or placebo. On the seventh postoperative day a segment of ileum surrounding the anastomosis was resected. The segments were tested for breaking strength or were histologically measured for anastomotic thickness. Results. The ileal anastomotic breaking strength in the rGH group was 181 ± 8.4 g (mean ± standard error). The breaking strength of ileal anastomoses in the placebo group was 133 ± 6.9 g (P < 0.05). The rGH group demonstrated a greater anastomotic thickness (1.65 ± 0.116 mm) than the placebo group (1.17 ± 0.113 mm, P < 0.05). Of placebo rats 14.7% developed anastomotic leaks compared to 0% of rGH-treated animals (P < 0.05). Conclusions. RGH increased the ileal anastomotic breaking strength by 36% in radiated rats. The anastomotic leak rate was reduced from 14.7% in the placebo group to 0% in the rGH group. These findings correlated with a 41% increase in the thickness of the anastomotic connective tissue in the rGH group. Clinical investigation in selected patients is warranted.