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 its stimulating effect on the healing of experimental colonic anastomoses.

METHODS

Rats were treated with biosynthetic growth hormone (bGH); the anastomotic breaking strength, collagen content, and collagen deposition rate (labeling of collagen with 14C-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 bGH treatment was started at operation and continued during the healing period. No effect on these parameters was seen, however, when treatment 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 deposition 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 given bGH from 7 days before operation until day 4 after operation, resulting 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 deposition rate of the anastomotic segment.