Mast cell degranulation and parenchymal cell injury in the rat mesentery

Objective: The objective of this study was to explore the degree of parench ymal cell injury after mast cell degranulation by application of compound 4 8/80 (CMP 48/80) in the absence of adherent leukocytes in the rat mesentery . Methods: Rats were rendered leukopenic by injection of an antibody against leukocytes, and the mesentery mas superfused with CMP 48/80 during intravit al microscopy. The extent of cell injury was determined using a fluorescent cell viability indicator, propidium iodide (PI). In an additional group, m ast cell degranulation with CMP 48/80 mas prevented by using the mast cell stabilizer Ketotifen. Results: After a reduction in the number of circulating leukocytes, mast ce ll degranulation produced a mild increase in parenchymal cell injury. The i njury levels significantly increased when individual regions of the mesente ry were compared. Stabilization of the mast cells with Ketotifen reduced th e injury to below baseline values. Conclusions: In the absence of leukocyte adhesion to the endothelium, mast cell degranulation contributes to parenchymal cell injury in the mesentery.