With hyaluronidase digestion, what happens to staining of mucosubstances containing hyaluronic acid and chondroitin sulfates A and C?

• A. Marked loss of stain
• B. Increased staining
• C. No change
• D. Only proteins are stained

Answer: (A)

The main idea is that enzymes like hyaluronidase break down mucosubstances that contain hyaluronic acid and sulfated glycosaminoglycans such as chondroitin sulfates A and C. These components provide the negative charges and structural sites that many histochemical stains (like Alcian blue for acidic mucopolysaccharides) bind to. When hyaluronidase digests these substances, those binding sites are removed, so the tissue can no longer take up the stain effectively. That results in a marked loss of staining for the mucosubstances containing hyaluronic acid and the chondroitin sulfates. The other scenarios—staining increasing, no change, or staining only proteins—don’t reflect the effect of degrading these glycosaminoglycans.