hematoksiliineosin

Hematoksiliineosin, commonly known in English as hematoxylin and eosin staining (H&E), is the standard staining method used in light microscopy for histology and pathology. It provides contrasting colors that reveal tissue architecture and cellular details, with nuclei typically appearing blue or purple and cytoplasm and extracellular matrix appearing pink to red. The technique is widely used for routine examination of tissue sections from biopsies and surgical specimens.

The staining relies on two dyes with complementary affinities. Hematoxylin is a basic dye that binds to acidic structures such as nucleic acids, staining nuclei blue-to-purple after an oxidation and mordant step. Eosin is an acidic dye that binds to basic components of the cell and extracellular matrix, staining cytoplasm, collagen, and red blood cells pink to red. The choice of mordants and blueing steps influences color intensity and contrast, and various commercial hematoxylin formulations (for example Harris or Mayer’s) are used in laboratories.

Procedure overview: tissue sections that have been fixed and embedded in paraffin are deparaffinized and rehydrated, stained with hematoxylin, treated to enhance blueing, counterstained with eosin, then dehydrated, cleared, and mounted for microscopic examination. Staining time and differentiation steps can be adjusted to optimize contrast for specific tissues.

Applications and interpretation: H&E staining is used to assess tissue morphology, identify cellular and structural features, and aid in diagnosing diseases, including cancer, inflammatory conditions, and degenerative changes. Limitations include potential variability in color intensity due to fixation, section thickness, or reagent quality, and the need for supplementary stains or immunohistochemistry for specific diagnoses.

See also: other histological stains and staining protocols commonly used in pathology.