Histological features of wound repair: a comparison between experimental ileal and colonic anastomoses

Various histological parameters of wound repair have been studied in intestinal anastomoses in the rabbit in order to compare the healing processes in ileum and colon. The sequentional appearance of granulocytes, macrophages and fibroblasts has been studied from 3 h to 7 days after operation. Also, degree of necrosis, formation of capillaries and mucosal repair were analysed semi-quantitatively. Significant differences were observed between ileal and colonic anastomoses with respect to occurrence of granulocytes, necrosis and mucosal repair, particularly 7 days after operation. At that time, granulocytes and necrosis were virtually absent from ileal anastomoses, while mucosal integrity was restored in the majority of cases examined. In contrast, granulocytes and necrosis were still abundantly present in colonic anastomoses and mucosal repair was poor. These results support biochemical evidence that wounds in the ileum heal more rapidly than wounds in the colon. Possibly, the sustained presence of granulocytes, which are a potential source of collagenase activity, is important in this respect. Investigation of the same features of intestinal wound healing in rabbits with peritonitis induced by infection showed similar results and no differences were found between infected and non-infected animals.