Hematoxylin and Eosin Staining in Histology

Importance of Clearing Paraffin Embedded Sections

• Clearing in xylene removes excess paraffin, allowing for effective penetration of staining reagents.
• Ensures proper adhesion of stains to tissue sections by enhancing permeability.

Purpose of Staining Specimens with H&E

• Hematoxylin and Eosin (H&E) staining provides contrast, highlighting cellular structures.
• Hematoxylin stains nuclei blue, while eosin stains cytoplasm and extracellular matrix pink, facilitating tissue evaluation.

Step Responsible for Staining Cell Nuclei

• The hematoxylin staining step specifically targets and stains cell nuclei, making them visible under a microscope.

Purpose of the Blueing Step

• The blueing step involves adjusting the pH of the specimen, optimizing the visibility of hematoxylin-stained nuclei by altering the hue from purple to blue.

Avoiding Fixatives with Osmic Acid

• Osmic acid promotes black precipitate formation, which can interfere with regressive staining protocols, complicating the differentiation of tissue structures.

Consequences of Skipping the Eosin Counterstain

• Omitting eosin results in underrepresented cytoplasmic and connective tissue structures, leading to a less informative overall tissue morphology.

Active Coloring Agent of Hematoxylin

• Hematoxylin itself acts as the primary dye, offering color through its oxidized form, which binds to nuclear components.

Mordant Used in Aluminum Hematoxylin

• Aluminum ions serve as mordants in aluminum hematoxylin, enhancing the binding of hematoxylin to tissue components.

Oxidation Stabilizer in Ehrlich's Hematoxylin

• Sodium iodate is incorporated into Ehrlich's hematoxylin to stabilize oxidation and maintain the dye's effectiveness.

Step Promoted by Sodium Iodate

• Sodium iodate is used to hasten the oxidation step in the staining procedure, crucial for activating hematoxylin.

Harris Hematoxylin Characteristics

• Harris hematoxylin has a wine-like odor and a distinct deep purple-red color, often making it noticeable during staining procedures.

Hematoxylin Solution for Mucopolysaccharides

• The characteristic of staining mucopolysaccharides, such as cartilage and cement lines of bones, intensely blue is associated with Alcian blue.

Not Ideal for Frozen Sections

• Harris hematoxylin is not optimal for frozen section analysis due to its formulation affecting tissue morphology.

Stabilizer in Delafield's Hematoxylin

• A small amount of mercuric chloride is added to Delafield's hematoxylin to stabilize the oxidation process, maintaining the quality of the stain.

Recommended Routine Hematoxylin Solution

• Mayer's hematoxylin is preferred for routine use, especially when used in sequence with Celestine blue for effective nuclear and cytoplasmic staining.

Test your knowledge of the process and significance of Hematoxylin and Eosin (H&E) staining in histology. Learn about its role in confirming basic tissue type and localizing lesions in specimens.