Anastomotic healing of small bowel with or without chronic radiation damage in protein-deficient malnourished rats

Objective: To assess the influence of protein malnutrition on anastomotic healing in rat small bowel with or without chronic radiation damage. Design: Controlled laboratory study. Setting: University hospital, Sweden. Material: 60 male Sprague-Dawley rats. Intervention: A short segment of the distal ileum was exteriorised and irradiated (n = 30) or only exposed (n = 30), and 20 weeks later an anastomosis was made within this segment. Two weeks before anastomosis half of the animals in each group received rat chow in which the protein content had been reduced to 25%; standard rat chow was given to the remaining animals. Main outcome measurements: Weight changes, anastomotic bursting strength, amount of perianastomotic hydroxyproline, and number of anastomotic complications. Results: 13 animals in the irradiated group and 11 animals in the non-irradiated group died of intestinal obstruction or respiratory distress leaving 17 and 19 animals that could be evaluated. Body weight was significantly reduced in animals with protein restriction (p < 0.001). A two way ANOVA showed an association between bursting strength and irradiation (p = 0.02) but not bursting strength and protein restriction. Anastomotic complications were more common in irradiated than in non-irradiated animals irrespective of the nutrition given (8/8 and 8/9 compared with 2/9 and 2/10, p = 0.0006). Conclusion: Protein malnutrition had no influence on anastomotic healing in rat intestine with or without chronic radiation damage.