With digestion, mucins containing hyaluronic acid and chondroitin sulfate A&C will show what change in staining?

• A. Marked loss of staining
• B. Increased staining
• C. No change
• D. Color shift

Answer: (A)

Acid mucopolysaccharides in mucins, such as hyaluronic acid and chondroitin sulfate, give mucins their negative charges that bind cationic stains like Alcian blue. When tissue is digested with enzymes that break down these glycosaminoglycans—hyaluronidase for hyaluronic acid and related enzymes for chondroitin sulfate—the acidic components are removed. With those charges reduced, the mucin no longer attracts the dye as strongly, resulting in a marked loss of staining. In other words, the digestion strip away the components responsible for the stain, so you’d see a pronounced decrease rather than an increase, no change, or just a color shift.