Which type of tissue section preparation is typical for this lipid-staining technique?

• A. Frozen
• B. Paraffin-embedded
• C. Resin-embedded
• D. Decalcified

Answer: (A)

Lipids are soluble in the organic solvents used during routine tissue processing, so to visualize them with lipid-specific dyes, you need to preserve the lipids in place. Frozen tissue sections are prepared without dehydration and clearing steps, which means the lipids aren’t dissolved away. This preserves intracellular lipid droplets, allowing dyes like Oil Red O or Sudan stains to bind and highlight them effectively.

Paraffin-embedded processing involves dehydration with alcohols and clearing with xylene, which extracts lipids and makes lipid staining unreliable. Resin-embedded processing also uses solvents and embedding media that can remove lipids. Decalcification is a separate step for hard tissues and doesn’t address lipid preservation, so it isn’t the method that enables lipid staining.