Experimental study of intraperitoneal suramin on the healing of colonic anastomoses

Introduction: The effect of the antiangiogenic agent suramin on the healing of colonic anastomoses was studied in a rat model. Methods: Rats underwent an end-to-end colonic anastomosis and its healing was tested by measuring bursting pressure, hydroxyproline content and number of newly formed vessels. For the bursting pressure experiment suramin was given intraperitoneally in a dose of 200 mg/kg (maximal tolerable dose) and 100 mg/kg. Hydroxyproline content and vessel density were only tested at 100 mg/kg since the toxicity at this dose was lower whereas bursting pressure was still diminished. Results: There were no deaths. On the fourth day after operation bursting pressure in the control group was significantly higher than that in rats treated with suramin 200 mg/kg (P = 0.006) and 100 mg/kg (P = 0.002). Rupture occurred at the anastomotic line. On day 7, this difference was not statistically significant. Four days after the operation, the hydroxyproline content and vessel density were significantly below that in control segments (hydroxyproline: 10.3 versus 7.8 mu g per mg dry weight; vessel content: 85.7 versus 49.6 vessels per x 100 field for control and suramin-treated rats respectively). On the seventh day no difference in hydroxyproline levels was seen but the vessel density was still diminished significantly (P = 0.04). Conclusion: Experimentally, suramin significantly inhibits and delays healing of colonic anastomoses.