Zinc sulfate acts as a protein coagulant and provides which features?

• A. Nuclear detail and better paraffin infiltration
• B. Lipid preservation and cytoplasmic retraction
• C. Decalcification of bone
• D. Removal of calcium deposits

Answer: (A)

Zinc sulfate works as a protein coagulant in fixatives by rapidly precipitating and stabilizing proteins, which helps lock in nuclear proteins and preserve nuclear detail. This coagulant action tends to produce crisp chromatin and well-defined nuclei, giving excellent nuclear detail. It also enhances tissue permeability and penetration during embedding, leading to better paraffin infiltration and overall section quality. It does not decalcify bone or remove calcium deposits, and lipid preservation isn’t the primary benefit of this coagulant. So the combination of improved nuclear detail and better paraffin infiltration best reflects zinc sulfate’s role.