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 c ancers have resulted in significant rates of morbidity and mortality. The o bjective of this study was to evaluate the effect of rGH on the breaking st rength and thickness of radiation-injured ileal anastomoses in an animal mo del. Material and methods. Sprague-Dawley rats were treated with 1800 cGy of pel vic irradiation in a single fractionation. Seventeen weeks following pelvic teletherapy an ileo-ileostomy was performed. The rats were randomized to r eceive 2.0 mg/kg/day of rGH for 7 days or placebo. On the seventh postopera tive day a segment of ileum surrounding the anastomosis was resected. The s egments were tested for breaking strength or were histologically measured f or 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 anastomo ses in the placebo group was 133 +/- 6.9 g (P < 0.05). The rGH group demons trated 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 anast omotic leaks compared to 0% of rGH-treated animals (P < 0.05). Conclusions. RGH increased the ileal anastomotic breaking strength by 36% i n radiated rats. The anastomotic leak rate was reduced from 14.7% in the pl acebo group to 0% in the rGH group. These findings correlated with a 41% in crease in the thickness of the anastomotic connective tissue in the rGH gro up. Clinical investigation in selected patients is warranted. (C) 1999 Acad emic Press.