Bacterial load and inflammatory reaction in the bowel wall after colonic obstruction. An experimental study in rats.

To quantify the inflammatory reaction to obstruction, alkaline phosphatase and myeloperoxidase activities were measured in specimens of colonic wall from 60 rats. Twenty rats had undergone laparotomy and band obstruction, 20 laparotomy without obstruction and 20 had no operation. The mean activities of both enzymes were increased proximal but not distal to the obstruction, that of alkaline phosphatase significantly so. Despite increase in the number of bacteria, both proximal and distal to the obstruction, no signs of bacterial invasion of the bowel wall were seen either on histological examination or culture. These findings indicate that mechanical factors may be more important than bacteria in causing the increased inflammatory reaction in bowel wall proximal to an obstruction.