Effect of colonic obstruction on the distribution of matrix metalloproteinases during anastomotic healing

Abstract

Background: Anastomotic dehiscence is common after surgery for colonic obstruction. The strength of an anastomosis is dependent on collagen, which is degraded by matrix metalloproteinases (MMPs). The aim of this study was to determine the distribution of the MMPs and their inhibitor, tissue inhibitor of metalloproteinases (TIMP) 1 in an experimental model of colonic obstruction, with and without resection and anastomosis. Methods: The distal colon of rabbits was obstructed with a Silastic ring for 24 h and then either the ring was removed or the obstructed segment was resected and an anastomosis formed. Rabbits were killed immediately or at intervals for up to 7 days after operation. The distribution of the MMPs and TIMP-1 was examined by indirect immunofluorescence. Results: MMPs and TIMP-1 were present throughout the descending colon for 24 h in both groups. They persisted to the third day in rabbits with an anastomosis but by day 7 were restricted to the suture line. Their presence correlated with microscopic damage. Conclusion: The extensive distribution of the MMPs suggests that these enzymes contribute to anastomotic dehiscence, but only in the immediate postoperative period.