Electron microscopic changes of bone marrow-derived cultured mast cells after injection into the skin of genetically mast cell-deficient W/Wv mice

Abstract

Phenotypes of bone marrow-derived cultured mast cells are different from those of connective tissue-type mast cells (CTMCs) that are found in the peritoneal cavity and the skin. When cultured mast cells of WBB6F1 - +/+ mouse origin were directly injected into the skin of genetically mast cell-deficient WBB6F1 - W/Wv mice, mast cells appeared in both the dermis and the subcutaneous tissue (beneath the panniculus carnosus). In contrast to cultured mast cells, mast cells that were observed in either the dermis or the subcutaneous tissue were stained with berberine sulfate, suggesting the content of heparin. Cultured mast cells acquired the electron microscopic features of CTMC in either the dermis or the subcutaneous tissue of WBB6F1 - W/Wv mice, but the electron density of mast-cell granules was significantly higher in the dermis than in the subcutaneous tissue. Such an electron microscopic difference was also observed after the injection of purified peritoneal mast cells of WBB6F1 - +/+ mice into the skin of WBB6F1 - W/Wv mice. From the present study, we suggest that the electron density of mast-cell granules in the skin of WBB6F1 - W/Wv mice is not dependent on the type of injected mast cells but on the anatomical sites at which the injected cells are located.