After enzymatic digestion, which components show marked loss of staining?

• A. Hyaluronic acid and chondroitin sulfate A&C
• B. Glycogen
• C. Mucin
• D. Sialomucins

Answer: (A)

Acidic glycosaminoglycans drive this staining. Alcian blue binds to negatively charged mucopolysaccharides like hyaluronic acid and chondroitin sulfate. When tissue is treated with enzymes that specifically digest these polymers—hyaluronidase breaking down hyaluronic acid and chondroitinase digesting chondroitin sulfates—the negative charges and binding sites are removed. As a result, Alcian blue staining diminishes markedly. Other substances listed, such as glycogen, mucin, or sialomucins, aren’t targeted by these enzymes in the same way, so their staining wouldn’t show the same pronounced loss after this enzymatic treatment.