Trichrome
Trichrome staining is a histological staining method that uses two or more acid dyes in conjunction with a polyacid. Staining differentiates tissues by tinting them in contrasting colours. It increases the contrast of microscopic features in c ...
stains are
staining
Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissues), in cytology (microscopic study of cells), and in the ...
methods in which three anionic
dye
A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...
s are used, in conjunction with either
phosphomolybdic acid
Phosphomolybdic acid is the heteropolymetalate with the formula . It is a yellow solid, although even slightly impure samples have a greenish coloration. It is also known as dodeca molybdophosphoric acid or PMA, is a yellow-green chemical compound ...
(PMA), phosphotungstic acid (PTA), or a mixture of these heteropolyacids. Probably the first trichrome method was that of Frank B Mallory, an American pathologist, first published in 1900. Unfortunately, none of Mallory's publications (they go from 1891 to 1938) provide any explanation of the rationales of either his trichrome or his phosphotungstic acid-haematoxylin (PTAH) method. Nobody knows why Mallory introduced heteropolyacids into microtechnique.
Mallory's trichrome method, using acid fuchsine followed by a solution containing PTA, orange G and aniline blue, provides dark red nuclei, orange erythrocytes, and blue collagen fibres, cartilage matrix and mucus.
[Kiernan JA (2008) Histological and Histochemical Methods. Theory and Practice. 4th ed. Bloxham, UK: Scion. {{ISBN, 978-1-904842-42-2] In 1915, M. Heidenhain introduced azocarmine G in place of the acid fuchsine of Mallory's method. Heidenhain also introduced visually controlled destaining to provide for different colours in cell nuclei (dark red), collagen (blue) and a variety of colours in cytoplasm.
References
Staining