Effect of early versus delayed postoperative injection of 5-fluorouracil plus interferon-alpha on colonic healing

The purpose of this study was to determine whether delayed, postoperative, intraperitoneal treatment with 5-fluorouracil (5-FU) plus interferon-alpha- 2a (IFN) has adverse effects on colonic healing, as does early treatment. S eventy male Wistar rats underwent colonic anastomoses. The rats were random ized to one of four groups. Early intraperitoneal injection was given to gr oups 1 and 2 which was repeated once daily for the first 3 postoperative da ys. Treatment was delayed in groups 3 and 4, from the 4th to the 7th postop erative day. A 0.9% NaCl solution was injected in the rats of control group s I and 3. In groups 2 and 4, we infused 5-FU (20 mg/kg/day) and IFN (45,00 0 IU/kg/day). All the animals were sacrificed on the 8th postoperative day. The anastomotic rupture rate was significantly higher in the rats of group 2 compared to control group 1 (p < 0.05), while there were no differences between groups 3 and 4 (p > 0.05). Abscess formation and adhesions were mor e frequent in group 2 compared to control group 1, while no differences wer e observed between groups 3 and 4. Anastomotic bursting pressure was statis tically significantly lower in the rats of group 2 compared to group I (p < 0.05); no differences were noticed between groups 3 and 4 (p > 0.05). Simu ltaneous histologic evaluation showed a more profound inflammatory reaction and delayed anastomotic healing in group 2 compared to control group 1; th ere were, however, no differences between groups 3 and 4. In conclusion, th e immediate, postoperative, intraperitoneal injection of 5-FU plus IFN impa irs colonic healing while delayed treatment (starting on the 4th postoperat ive day) has no adverse effects on wound healing.