Hematoxylin and Eosin (H&E)

� The Hematoxylin is a basic dye that stains acidic

components of cells a blue color.

� This characteristic is known as basophilia.

� Hematoxylin stains the nuclei of cells, and the RER of

the cytoplasm.

� Eosin is an acidic dye that stains the basic

components of the cells a reddish-pink color.

� This characteristic is known as acidophilia.

� Most of the cytoplasm of cells is stained by eosin.

� Bone matrix is also stained by eosin.

Periodic acid-Schiff (PAS) staining

� PAS is a widely used staining technique that stains the

neutral sugars of glycosaminoglycans a pink color.

� Common components stained positively with PAS

include mucus, glycogen, muco-protein, glycoprotein,

the basal lamina, organ capsules, blood vessels, etc.

Orcein

� Orcein staining is used to stain elastic fibers a dark

brown-purple color.

� This is used, for example, to show the elastic

components in the walls of arteries, or in the matrix

of elastic cartilage.

Osmium tetroxide

� Osmium is used to stain lipids a dark black color.

� It is very useful for demonstrating the myelin of

myelinated nerves, or lipid droplets in the liver or

steroid-secreting cells.

Toluidine blue

� Toluidine blue is a so-called metachromatic stain.

� It is a blue stain that stains specific components of tissues

a purple color.

� This change in staining color known as metachromasia.

� Metachromasia is seen in the matrix of hyaline cartilage,

or in the granules of mast cells.

Impregnation

� Impregnation is a staining technique in which

blocks of tissue are processed in solutions

containing metals such as silver or gold, which

attach to specific components in tissues.

� The silver or gold are then further processed

(reduced) and develop into dark metallic deposits.

� The stained blocks are then sectioned.

� Silver impregnation is widely used to stain

neurons and to demonstrate reticular fibers.

Vital staining

� Vital staining refers to the uptake of dyes by cells.

� If we inject Trypan blue into experimental animals,

the dye is rapidly engulfed by specific macrophages.

� We can use such vital staining to demonstrate the

Kupffer cells of the liver.

Giemsa stain

� There are a variety of "Romanowsky-type" stains with

mixtures of methylene blue, azure, and eosin

compounds.

� Among these are the Giemsa stain and the Wright's stain

(or Wright-Giemsa stain).

� The latter is utilized to stain peripheral blood smears.

Connective tissue stains

� The trichrome stain helps to identify the supporting

collagenous stroma in sections from a variety of organs.

� Trichrome helps in identifying normal structures, such

as connective tissue capsules of organs, the lamina

propria of gastrointestinal tract, and the broncho-

vascular structures in lung.

Malory stain

Masson`s trichrome

� Examples of trichrome stain:

�Malory stain: stains collagen blue

�Masson`s trichrome: stains collagen

green