GROWTH-HORMONE INCREASES THE COLLAGEN DEPOSITION RATE AND BREAKING STRENGTH OF LEFT COLONIC ANASTOMOSES IN RATS

Background. The purpose was to investigate how growth hormone exerts i ts stimulating effect on the healing of experimental colonic anastomos es. Methods. Rats were treated with biosynthetic growth hormone (bGH); the anastomotic breaking strength, collagen content, and collagen dep osition rate (labeling of collagen with C-14-proline) were compared to saline treated controls. Results. bGH increased the breaking strength when the rats were treated before and after the operation and when bG H treatment was started at operation and continued during the healing period. No effect on these parameters was seen, however, when treatmen t was given only before operation. The collagen deposition rate of the intact colon was accelerated from 0.6% to 1.0% per hour at operation after 7 days of preoperative treatment. The anastomotic collagen depos ition rate was increased on day 4 from 4.4% in the controls to 9.0% in the anastomosed rats given bGH from operation and to 12.9% in rats gi ven bGH from 7 days before operation until day 4 after operation, resu lting in a higher anastomotic collagen content. Conclusions. Treatment of rats with bGH in the healing phase increases the breaking strength of colonic anastomoses caused by a stimulation of the collagen deposi tion rate of the anastomotic segment.