Which stain is used for acid mucopolysaccharides?

• A. Alcian Blue 1.0 and 2.5, colloidal iron, mucicarmine
• B. Alcian Blue 2.5 and colloidal iron
• C. Congo Red
• D. PAS

Answer: (A)

Acid mucopolysaccharides are detected using Alcian Blue because this dye binds to the negatively charged groups of mucosubstances like sulfated and carboxylated glycosaminoglycans. The pH of the Alcian Blue stain determines which types are highlighted: at very acidic pH (around 1.0) it stains sulfated mucosubstances, while at pH 2.5 it stains both sulfated and carboxylated mucosubstances. Using both pH values together broadens the detection of acidic mucopolysaccharides. Colloidal iron is added to intensify and clarify the blue staining, making the acid mucosubstances more conspicuous, and mucicarmine is included as a counterstain to color mucins pink/magenta, helping distinguish mucin-rich areas. So this combination specifically targets and enhances visualization of acid mucopolysaccharides within tissue, with Alcian Blue providing the blue stain for the acidic components.