Cells are tipically colourless and transparent, so that, in order to make them visible, histological sections have to be stained.
In these last years the popularity of ready-to-use staining solutions as a useful implement in laboratories has increased. Beyond several important functional advantages (safety, time saving, decrease of work load, easy estimate of cost/test ratio), ready-to-use Bio-Optica solutions offer excellent, reproducible results.
The most used stain for routine diagnosis in histology and histopathology laboratories is hematoxylin and eosin stain (H&E). This happens because when this stain is properly performed, it allows to show a wide range of cytoplasmic, nuclear, and extracellular matrix features and also because it is a relatively simple stain to carry out on paraffin or frozen sections; in fact, this kind of stain is still used today, as it has been used for century.
In histopathology, an experienced pathologist could be able to diagnose a high number of cases just by using an H&E stain. A small numbers of slides can be stained manually while in laboratories with a high workload, the staining process is performed by automatic stainers like the Bio-Optica AUS 240 Plus.
Since the combination of using a variety of both hematoxylin and eosin stains gives the possibility to laboratories to customize the desired results with few issues, it is common to choose stains to ensure consistent and repeatible quality.
Hematoxylin is used to show nuclear detail in cells which appear in blue to purple color. The intensity of coloration depends on two factors: the amount of DNA in the nuclei, and the time the sample spends in hematoxylin.
Mayer's hematoxylin is maybe the most nuclear staining solution used in routine histopathology. It gives a final color well balanced between nuclear and cytoplasmic staining in hematoxylin-eosin method.
Harris hematoxylin is a nuclear staining solution and it gives a deep, purple-blue stain. It is tipically used as regressive methods, but it can be also used for cytology or histology preparations.
Gill's hematoxylin is offered in three different composition. Gill 1, used for citology preparations; Gill 2, used in the progressive method of staining; and Gill 3 that is preferred in histology.
Gill 1 hematoxylin (similar to Carazzi's hemalum)
Gill 2 hematoxylin (similar to Mayer's hemalum)
Gill 3 hematoxylin (similar to Harris hematoxylin for histology)
Weigert hematoxylin is typically used in special stains, like Verhoff-Van Gieson stain. It can demonstrate more tissue structures than alum hematoxylins, such as myelin and elastin fibers.
Weigert A ferric hematoxylin
Weigert B ferric hematoxylin
Carazzi’s Hematoxylin is a progressive solution giving litttle background staining. The result obtained with this stain are blue nuclei.
If hematoxylin is used to stain the nuclear cells, Eosin is the most used counterstain that distinguishes between the cytoplasm and nuclei of cells. It is typically pink, with different grades of pink based on the different types of connective tissue fibers.
Eosin Y is the most used form of eosin and it is used in both water and alcohol. To highlight the staining of the eosin it is enough to add a small quantity of acetic acid.
Eosin Y aqueous solution 1%
Eosin Y alcholic solution 0,5%