Which staining method is best to visualize myelin in nervous tissue?

• A. Luxol Fast Blue
• B. Protargol
• C. Phosphotungstic acid hematoxylin
• D. Iron hematoxylin

Answer: (A)

The key idea is to use a stain that specifically highlights the lipid-rich myelin sheaths to make white matter stand out. Luxol fast blue does this by binding to the lipids in myelin, turning the myelin sheaths blue. When paired with a counterstain (commonly cresyl violet), neurons and other tissue elements take on contrasting colors, so myelin appears as distinct blue regions against the background. This makes it easy to see the organization of white matter and to detect demyelination as pale or absent blue areas.

Other stains listed are not selective for myelin. Protargol is a silver stain that highlights nerve fibers but isn’t specific for myelin lipids. Phosphotungstic acid hematoxylin staining emphasizes certain tissue components like muscle and connective tissue rather than myelin. Iron hematoxylin stains nuclei and chromatin-rich structures and isn’t a reliable method for visualizing myelin.