Rapid intestinal ischaemia-reperfusion injury is suppressed in geneticallymast cell-deficient Ws/Ws rats

Ws/Ws rats have a small deletion of the c-kit gene, and are deficient in bo th mucosal and connective tissue-type mast cells. In this study, the role o f mucosal type mast cells (MMC) in the development of intestinal ischaemia- reperfusion injury was investigated in Ws/Ws rats. Autoperfused segments of the jejunum were exposed to 60 min of ischaemia, followed by reperfusion f or various time periods. The epithelial permeability was then assessed by t he Cr-51-EDTA clearance rate. In the control (+/+) rats, the maximal increa se in mucosal permeability was achieved at 45 min of reperfusion. In contra st, this increase was significantly and potently attenuated in the Ws/Ws ra ts. Mucosal alkaline phosphatase activity decreased in the control (+/+) ra ts, but was not altered in the Ws/Ws rats. There were no differences in muc osal myeloperoxidase activity, indicating that granulocytes did not contrib ute to tissue injury. These results provide direct evidence for the role of mast cells in the pathogenesis of intestinal ischaemia-reperfusion injury.