Objective: The objective of this study was to explore the degree of parenchymal cell injury after mast cell degranulation by application of compound 48/80 (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 was superfused with CMP 48/80 during intravital microscopy. The extent of cell injury was determined using a fluorescent cellviability indicator, propidium iodide (PI). In an additional group, mast cell degranulation with CMP 48/80 was prevented by using the mast cell stabilizer Ketotifen.
Results: After a reduction in the number of circulating leukocytes, mast cell degranulation produced a mild increase in parenchymal cell injury. The injury levels significantly increased when individual regions of the mesentery were compared. Stabilization of the mast cells with Ketotifen reduced the 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.