A study of rat intestinal wound healing in the presence of radiation injury.

Anastomotic dehiscence is a common complication following the resection of intestine with late radiation damage, and can occur even after wide resection of obviously compromised tissue. In this study using male rats, exteriorized segments of terminal ileum and/or the fatty appendages of the testes were exposed to single doses of irradiation (10, 15 and 20 Gy) producing early and late damage of varying severity. Wounds made at intervals from 2-24 weeks after irradiation in normal or irradiated ileum were repaired immediately and wrapped in normal or irradiated appendages. Post mortem examination of the wounds 4-7 days later showed that, in general, control wounds made in unirradiated tissues healed soundly. The incidence of wound breakdown in irradiated tissues was dose-dependent. After irradiation of the ileum alone, the frequency of suture line dehiscence increased with the interval between irradiation and wounding. When the ileum and appendages or appendages alone had been irradiated, the frequency of dehiscence was increased from 2 weeks post-irradiation onwards. This study emphasizes the important role played by adhesions in rat intestinal wound healing and shows that dehiscence may occur if irradiated tissues are positioned next to a suture line made in normal rat intestine. The findings suggest that, in clinical practice, it may be advisable to ensure that anastomoses at risk from radiation damage area wrapped in unirradiated tissue such as omentum.