In Bouin solution, which component hydrolyzes nuclei?

• A. Picric acid
• B. Formaldehyde
• C. Acetic acid
• D. Copper acetate

Answer: (A)

Bouin solution fixes tissue with a combination of three agents, each doing a different job. The formaldehyde component cross-links proteins, helping preserve overall structure. The acetic acid component causes swelling and helps preserve delicate parts, contributing to better cytoplasmic detail and some nuclear morphology changes. The picric acid component is highly acidic and acts on nucleoprotein complexes in the nucleus, promoting hydrolysis of nuclear material. This acidic action on the nucleus is what makes nuclei appear altered under Bouin fixation, so the component responsible for hydrolyzing nuclei is the picric acid portion.