[Histonet] Collagen Staining

[Paul Bradbury]

Trying to stain collagen by using just the aniline blue solution from a 
trichrome method will not work. An acidified solution of aniline blue 
will non-selectively stain all acidophilic tissues (red cells, muscle, 
cytoplasm, collagen, etc.).
The reason that the trichrome methods distinguish collagen from other 
tissue structures is that red cells and muscle have been pretreated with 
phosphomolybdic acid prior to staining in aniline blue. The presence of 
the aniline blue in those tissues inhibits (for a period of  time) the 
attachment of the blue dye. The principles of the trichrome techniques 
depend on the molecular size of the dye molecules and the relative 
porosity of the tissue proteins that are to be stained.

To selectively stain collagen without any other background staining, I 
would suggest trying the following.

Bring the sections down to water as usual.
Treat the sections in 1% aqeous phosphomolybdic acid for 5 minutes
Drain off the acid. Do not wash as this will extract the PMA from the 
tissues.
Stain in acidified aniline blue (or any one of the blue or green stain 
solutions used in a trichrome method) for 3 minutes.
Rinse very briefly in distilled water. Just a few seconds, no longer.
Dehydrate quickly through graded alcohols.
Clear in xylene and mount.

What I believe will happen is that the PMA will block entry of the dye 
to all tissue structures except collagen, thus giving selective 
coloration of the collagen fibres.

Paul Bradbury
Kamloops, BC
Canada



Jo-Ann Bader, Ms. wrote:

>Good Morning Everyone,
>
>I am looking for a stain for Collagen without a background stain.  I have tried the Aniline blue from the Masson's Trichrome with unsatisfactory results.  
>
>Jo-Ann Bader
>
>
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