Neoadjuvant chemotherapy with 5-FU does not alter the strength of colon anastomosis in this rat model. A dose of 20 mg/kg induces significantly more intra-abdominal adhesions and histological alterations at the anastomotic site.

Glutamine administration stimulates mucosal growth and preserves the morphology of the intestine. Theoretically, it could improve colonic anastomotic healing after radiotherapy (RT)-induced epithelial damage and mucosal atrophy induced by total parenteral nutrition (TPN). To investigate this issue, the rectosigmoid colon in male Wistar rats was irradiated to a total dose of 25 Gy. Five days after the end of RT, side-to-side anastomosis was constructed between the irradiated rectosigmoid and the nonirradiated caecum. Postoperatively, animals were divided in three groups: group I, normal diet orally; group II, TPN; group III, TPN enriched with 2% glutamine (Gln-TPN). All animals decreased in weight during RT and after surgery. Weight regain postoperatively was better in the orally fed animals in comparison with the parenterally fed animals (I vs. II and III; p < 0.01). Colonic anastomotic bursting pressure (BP) and bursting wall tension (BWT) were significantly less in group II in comparison with groups I and III (II vs. I and III; p < 0.01). BP and BWT were comparable in groups I and III. No significant differences were found between all the groups in gut bacterial translocation to the blood or to the mesenterical lymph nodes. Conclusively, Gln-TPN can play a role in counteracting the negative effect of food deprivation on the healing of irradiated colonic anastomoses. Postoperative Gln-TPN does not influence gut bacterial translocation in this rat model.

SUMMARY To study the effects of preoperative radiochemotherapy (RCT) on the healing of colonic anastomosis, the rectosigmoid colon in male Wistar rats was irradiated up to an end dose of 41.6 Gy (RT) or sham-irradiated (SR). During the last 5 days of the irradiation schedule, 5-fluorouracil (5-FU) was administered intraperitoneally in either a high dose (20 mg/kg, chemotherapy-high dose [CH]) or a low dose (10 mg/kg, chemotherapy-low dose [CL]). Animals were randomly arranged into six groups: group I, control (SR + saline intraperitoneally); group II, RT only; group III, SR + CL; group IV, RT + CL; group V, SR + CH; group VI, RT + CH. Four days after RCT, a side-to-side anastomosis was constructed between the irradiated rectosigmoid and the nonirradiated caecum. Animals were killed 10 days postoperatively. No significant differences were found in the anastomotic bursting pressure or the bursting wall tension. In group VI, mitoses were less (P < 0.01) and mucosal ulceration was more (P = 0.03) pronounced compared to group I. Sclerotic arteries were seen in all irradiated groups and in animals that received high-dose 5-FU alone. 5-FU administration in high or low dose, with or without RT, induced more inflammation in the submucosa compared to controls (P < 0.05). Conclusively, RCT has no detrimental effect on the mechanical strength of colonic anastomosis in this rat model. However, RCT with high-dose 5-FU induces more histological alterations at the anastomotic site.

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Glutamine administration stimulates mucosal growth and preserves the morphology of the intestine. Theoretically, it could improve colonic anastomotic healing after radiotherapy (RT)-induced epithelial damage and mucosal atrophy induced by total parenteral nutrition (TPN). To investigate this issue, the rectosigmoid colon in male Wistar rats was irradiated to a total dose of 25 Gy. Five days after the end of RT, side-to-side anastomosis was constructed between the irradiated rectosigmoid and the nonirradiated caecum. Postoperatively, animals were divided in three groups: group I, normal diet orally; group II, TPN; group III, TPN enriched with 2% glutamine (Gln-TPN). All animals decreased in weight during RT and after surgery. Weight regain postoperatively was better in the orally fed animals in comparison with the parenterally fed animals (I vs. II and III; p < 0.01). Colonic anastomotic bursting pressure (BP) and bursting wall tension (BWT) were significantly less in group II in comparison with groups I and III (II vs. I and III; p < 0.01). BP and BWT were comparable in groups I and III. No significant differences were found between all the groups in gut bacterial translocation to the blood or to the mesenterical lymph nodes. Conclusively, Gln-TPN can play a role in counteracting the negative effect of food deprivation on the healing of irradiated colonic anastomoses. Postoperative Gln-TPN does not influence gut bacterial translocation in this rat model.