Masson Trichrome Principle Flashcards
What are trichromes?
Multi dye methods used to differentiate between tissue components, highlighting collagen fibres, muscle fibres, and cytoplasm.
How do trichrome stains work?
Based on dye permeability, molecular size, and tissue affinity.
What type of dyes do most trichrome stains use?
Acidic dyes that bind to basic (positively charged) tissue elements.
What is the permeability of red blood cells (RBCs) in relation to dye molecules?
RBCs are the least permeable and are stained with the smallest molecule dyes.
What is an example of a small dye molecule?
Acid fuchsin.
What does the large dye molecule, Light green, penetrate?
Only penetrates porous areas like collagen but not dense cytoplasm or muscle.
What series of dyes are used in trichrome staining?
Celestine blue, Mayer’s haematoxylin, Ponceau red, acid fuchsin, and light green.
What do nuclei stain with in trichrome staining?
Both Celestine blue and Mayer’s haematoxylin to form an intensely blue nuclear stain.
Which dye can fully penetrate all tissue components, including RBCs?
Acid fuchsin.
What is the staining capability of Ponceau red compared to acid fuchsin?
Ponceau red can penetrate muscle and epithelia but not red blood cells.
How do the dyes bind to proteins in trichrome staining?
Dyes bind strongly to proteins, but their attachment to collagen is weaker compared to muscle.
What is the role of phosphomolybdic acid in trichrome staining?
Displaces smaller dyes from collagen fibres but retains the red dye in muscle and cytoplasm.
What does the addition of large dye, Light green, accomplish?
Stains collagen green by replacing the small dye that was removed.
What is the effect of rinsing with tap water in the process?
Lowers pH, intensifying the contrast between collagen and muscle/cytoplasm.
Fill in the blank: The smallest dye in trichrome staining is _______.
Acid fuchsin.
True or False: Collagen stains with the smallest dye molecules.
False.
What determines the staining colors in trichrome methods?
The permeability and porosity of different tissue elements.
