Fixative used for Acid mucopolysaccharides

• A. Mercuric chloride
• B. Bouin's
• C. Formalin
• D. Lead fixatives

Answer: (D)

Acid mucopolysaccharides (glycosaminoglycans) are highly negatively charged carbohydrate-rich components of connective tissue and mucus. To study them histochemically, tissues must retain these sticky, soluble glycoconjugates through fixation and processing. Lead-based fixatives stabilize acid mucopolysaccharides by forming insoluble lead salts with their sulfated and carboxylated groups, effectively anchoring them in place during dehydration and embedding. This preserves their native distribution and structure, allowing reliable visualization with stains that target these carbohydrates. Other fixatives, like mercuric chloride, Bouin’s, or formalin, mainly fix proteins by cross-linking and can mask, extract, or alter carbohydrate components, reducing the integrity of mucopolysaccharide staining. Thus, a lead-based fixative is particularly suited for demonstrating acid mucopolysaccharides.