If blue-stained tissue is treated with hyaluronidase, what happens to the staining?

• A. Staining intensifies
• B. Staining remains the same
• C. Staining decreases or disappears
• D. Staining changes color

Answer: (C)

The staining fades or disappears because the blue stain (often Alcian blue) binds to acidic mucopolysaccharides like hyaluronic acid in tissue. Hyaluronidase digests hyaluronic acid, removing those binding sites. With fewer targets for the dye, the blue color diminishes or is lost. The enzyme doesn’t change the dye’s color or intensify it; it reduces the staining by destroying the substance the stain adheres to.