Histopathological Effects of Ischemia- Reperfusion on Intestinal Anastomotic Wound Healing in Dogs Efectos Histopatológicos de Reperfusión Isquemia en la Anastomosis Intestinal de Heridas Curadas en Perros

SUMMARY: The histopathological effects of three levels of ischemia-reperfusion (IR) on healing of intestinal anastomotic wound were investigated in dogs. Three groups of dogs in which superior mesenteric artery (SMA) and collaterals were isolated but not occluded (A-control), isolated and occluded immediately distal to the aorta with collateral interruption using an atraumatic arterial clip for fifteen minutes (B) and for forty-five minutes (C) prior to ileal resection and anastomosis after return of normal perfusion in occluded groups was done. Within each group, animals were anaesthesized on third and seventh post-operative day. Grossly, impaired abdominal wound healing, intra-abdominal adhesions and partial and complete anastomotic dehiscence occurred in groups B and C commensurate with intensity of ischemic injury. Histologically, light cellular infiltration with loose granulation tissue was observed in the control group with moderate neovascularization and epithelialization by the seventh day. With mild IR, moderate cellular infiltration was observed four days post operation, but heamorrhage and oedema persisted with minimal mucosal regeneration at seven days post operation. With profound IR, sloughing of the mucosa with cellular infiltration at four days with absence of mucosal regeneration and persistence of inflammatory cellular infiltrates minimal neovascularization and dense granulation tissue. Neutrophilia in the immediate post operative period appears significant to impaired healing due to ischemia-reperfusion. KEY WORDS: Histopathology; Ischemia-reperfusion injury; Intestinal anastomoses; Wound healing