Which stain is most appropriate for highlighting myelin in nervous tissue?

• A. Luxol fast blue
• B. Masson's Trichrome
• C. Oil Red O
• D. Periodic Acid Schiff's

Answer: (A)

The key idea is using a stain that specifically binds the lipid-rich myelin sheath to make it stand out in nervous tissue. Luxol fast blue does just that: it is a basic dye that preferentially binds the lipids in myelin, giving myelin a distinct blue color. This makes it the go-to stain for visualizing myelin and for spotting demyelinating areas, especially when used in combination with a counterstain to visualize other structures (for example, cell bodies stained purple with cresyl violet).

Masson's Trichrome is designed to differentiate connective tissue components like collagen, muscle, and keratin, not myelin, so it won’t highlight myelin effectively. Oil Red O stains lipids, which means it can highlight lipid-rich structures, but it’s typically used on frozen sections and is not as specific or widely used for detailed myelin visualization in standard nervous-tissue slides. Periodic acid–Schiff stains carbohydrates and mucopolysaccharides, not myelin. So the stain best suited to highlight myelin is Luxol fast blue.