BACKGROUND:Suture line recurrence continues to be an important cause of failure following curative resection for colorectal carcinoma. Our aim was to determine whether the nature of the suture material used affected the proliferative activity of colonic crypt cells at the anastomosis. METHODS ANDMATERIALS:Sprague‐Dawley rats were randomized into one control and three experimental groups. In each experimental group the proximal 2 cm of rectum were resected and anastomoses constructed with titanium clips, interrupted 6‐0 VicrylTM(Ethicon, Inc., Somerville, NJ), and interrupted 6‐0 silk. Control animals had a sham operation. One‐quarter of each group of rats were killed at 14, 30, 60, and 90 days. Each animal received intraperitoneal tritiated thymidine 30 minutes before death. Each anastomosis was harvested, and longitudinally oriented crypts were analyzed for the total number and position of labeled cells at five equal distances from the anastomosis. Random crypts were studied in the control group.RESULTS:Labeling indices were increased in almost all experimental groups at days 14, 30, 60, and 90. There were no persistent, statistically significant differences in labeling indices among the various suture materials.CONCLUSION:The type of suture material used did not significantly affect the proliferative rate in this animal model.