What does PAS stain highlight in liver tissue?

What does PAS stain highlight in liver tissue?

• A. Glycogen and other carbohydrate-rich substances; with diastase digestion, glycogen is removed to differentiate components.
• B. Lipid droplets.
• C. Proteins.
• D. Nucleic acids.

Answer: (A)

PAS staining targets carbohydrates. The reaction oxidizes vicinal diols in sugars to aldehydes, which then react with Schiff reagent to give a magenta color. In liver, glycogen is a major PAS-positive substance, so hepatocytes with glycogen stores stain vividly. Using diastase (amylase) before PAS digestion removes glycogen, so what remains helps distinguish glycogen from other carbohydrate-rich materials such as mucopolysaccharides and glycoproteins. This is why the best answer encompasses glycogen and other carbohydrate-rich substances, while lipids, proteins, or nucleic acids are not the primary targets of PAS in this context.

PAS staining targets carbohydrates. The reaction oxidizes vicinal diols in sugars to aldehydes, which then react with Schiff reagent to give a magenta color. In liver, glycogen is a major PAS-positive substance, so hepatocytes with glycogen stores stain vividly. Using diastase (amylase) before PAS digestion removes glycogen, so what remains helps distinguish glycogen from other carbohydrate-rich materials such as mucopolysaccharides and glycoproteins. This is why the best answer encompasses glycogen and other carbohydrate-rich substances, while lipids, proteins, or nucleic acids are not the primary targets of PAS in this context.