What is the recommended fixative approach when preparing tissues for fat or lipid staining?

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Multiple Choice

What is the recommended fixative approach when preparing tissues for fat or lipid staining?

Lipids must be preserved in the tissue for fat stains, and they are easily dissolved by the solvents used in ordinary paraffin processing. That’s why alcohol-based fixatives and dehydration steps ruin lipid staining. The best approach is to fix with a formaldehyde-based fixative (formalin) in a way that doesn’t involve alcohol extraction, then cut very thin cryosections (about 8–10 microns) and mount them in an aqueous medium. This combination keeps lipids intact long enough for dyes like Oil Red O or Sudan stains to reveal them under the light microscope. Using water fixation, ethanol or other alcohol-based fixatives, or paraffin/xylene processing would remove the lipids and prevent proper visualization.

Lipids must be preserved in the tissue for fat stains, and they are easily dissolved by the solvents used in ordinary paraffin processing. That’s why alcohol-based fixatives and dehydration steps ruin lipid staining. The best approach is to fix with a formaldehyde-based fixative (formalin) in a way that doesn’t involve alcohol extraction, then cut very thin cryosections (about 8–10 microns) and mount them in an aqueous medium. This combination keeps lipids intact long enough for dyes like Oil Red O or Sudan stains to reveal them under the light microscope. Using water fixation, ethanol or other alcohol-based fixatives, or paraffin/xylene processing would remove the lipids and prevent proper visualization.

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