What fixative is used for Alcian blue with hyaluronidase?

• A. 10% NBF
• B. Bouins
• C. 95% Ethanol
• D. Glutaraldehyde

Answer: (A)

For Alcian blue with hyaluronidase, the fixative should preserve acidic mucopolysaccharides without masking them or interfering with the enzymatic digestion. Neutral buffered formalin (10%) provides reliable preservation of tissue morphology and the mucopolysaccharide components, while remaining compatible with hyaluronidase digestion and subsequent Alcian blue staining. It avoids the strong, complex cross-linking and pigment issues seen with other fixatives.

Bouin’s solution can preserve mucins but introduces picric/acetic acid components that can cause staining artifacts and background issues, making it less ideal for this specific stain with enzymatic digestion. Ethanol can extract and shrink tissue and mucins, compromising staining quality. Glutaraldehyde cross-links very tightly and is generally not suitable for routine histochemical staining like Alcian blue with hyaluronidase.