Pyronin Y as a fluorescent stain for paraffin sections

Area of Science:

• Histology
• Biochemistry
• Cell Biology

Background:

• Pyronin Y is traditionally used with Methyl Green for nucleic acid staining.
• Its fluorescent properties for nucleic acids are utilized in flow cytometry.
• The use of Pyronin Y as a fluorescent stain in paraffin sections is underexplored.

Purpose of the Study:

• To investigate the potential of Pyronin Y as a fluorescent stain for paraffin-embedded tissue sections.
• To characterize the fluorescence properties of Pyronin Y in various tissue components.

Main Methods:

• Staining of paraffin tissue sections with Methyl Green-Pyronin Y.
• Examination of stained sections using confocal laser-scanning microscopy.
• Staining with Pyronin Y alone.
• RNase pretreatment of sections followed by microscopy.

Main Results:

• Methyl Green-Pyronin Y staining revealed strong green/red fluorescence in red blood cells, elastic fibers, zymogen granules, and cell membranes.
• Cell nuclei appeared non-fluorescent.
• Confocal microscopy enhanced image resolution and selectivity.
• Pyronin Y alone showed similar fluorescence.
• RNase treatment reduced cytoplasmic staining but minimally affected fluorescence in specific structures.

Conclusions:

• Pyronin Y is effective as a fluorescent stain for paraffin tissue sections, highlighting specific cellular and extracellular components.
• Its fluorescence is distinct from nucleic acid staining, with notable signals in erythrocytes, elastic fibers, and granules.
• Confocal microscopy is beneficial for visualizing these fluorescent signals.
• The observed fluorescence in certain structures is independent of RNA content.