Fixation with neutral buffered formalin (NBF) influences how the cytoplasm takes up hematoxylin by causing it to

• A. Take Up More Hematoxylin
• B. Take Up Less Hematoxylin
• C. Not Change
• D. Dissolve Hematoxylin

Answer: (A)

Fixation with neutral buffered formalin preserves and cross-links cellular components, which changes how dyes interact with tissue. Hematoxylin is a basic dye that binds to acidic, basophilic structures such as nucleic acids and ribonucleoproteins. By fixing with formalin, cytoplasmic RNA and other basophilic constituents are preserved and become more accessible for binding, increasing the cytoplasm’s basophilic character. As a result, more hematoxylin can attach to cytoplasmic sites, so the cytoplasm takes up hematoxylin more than it would in unfixed tissue. The other possibilities don’t fit how fixation influences dye–tissue interactions—fixation doesn’t dissolve the stain or leave uptake unchanged, and it doesn’t inherently reduce uptake.