Cytochemistry of mast cells: new fluorescent methods selective for sulfated glycosaminoglycans

The development and application of simple and selective fluorescent methods for routine detection of mast cells are of considerable interest because these cells play an important role in health and disease. In the present study, aspects of staining of sulfated glycosaminoglycans with carbocyanines, aryloxazoles, and a ruthenium(II) complex are discussed. The most suitable of these compounds for visualizing mast cells in smears and tissue sections are DiOC1 (3), Q-dmPOPOP, PyPO, and Rubipy, which have been practically overlooked as cationic fluorochromes for fixed cells. Bicolour fluorescence allowing simultaneous observation of mast cells and other cell types and tissue components by application of these dyes in combination with haematoxylin and/or eosin, or by counterstaining with other fluorochromes or fluorescent complexes is particularly useful for routine histopathological studies. Simple and reliable staining procedures, bright emission, high sensitivity and stability, permanent mounting, and possibilities for combined use with other histochemical methods are the most relevant advantages of these mast cell fluorochromes.