Ponceau Fuchsin

From:Lee & Peggy Wenk

In reply to Patsy Ruegg question on trichrome staining
(sorry, my "reply" button doesn't seem to be working, 
so I'm trying a "new message" to send this).

Actually, a wide variety of anionic red dyes can be used, or even
anionic dyes of other colors, like orange.

For example, acid fuchsin, azocarmine, Biebrich scarlet, 
chromotrope 2R, and a whole slew of ponceau dyes all work.

Dick Dapson did a great article in the Feb. 1998 issue of
the Mich. Society for Histotechnologists newsletter, the

He said, at the time, there were 17 dyes listed that contained
the word "ponceau" in Conn's Biological Stains (9th edition, 1977).
This list did not include 3 additional dyes now on the market
with the name ponceau (which, BTW, means "poppy" in
French, for its red color.)

The article had drawings of various ponceau dye molecules,
showing that some had 2 benzene rings, while others had
3. And some had 2, 3 or 4 sulfonic groups, which is what
binds to the connective tissue. Some of the sulfonic groups
were on the same side of the dye molecule, some were
at one end, some were all over the place.

In general, the more benzene rings, the deeper the color.
The more sulfonic groups, the more likely the dye is to
find a site on the tissue to bind to. The more evenly
distributed the sulfonic groups (not all at one end), the
more likely it would stay bonded to the tissue. The different
number of sulfonic groups and the different locations gave
a different shade of red.

So, of the 20 ponceau dyes that he looked at, Dick
recommended Ponceau S, Color Index number 27195
as the darkest color, most stable, most likely to bind, etc.

I ordered some, and I like the final results. It is a deep
red, and the students' Masson trichrome looked great
for their registry exams.

However, it is a rosier red than what we are currently using
in our histology lab, so it will be a matter of how much the
pathologists complain about the slight change of color. Frankly,
I don't think they would even notice, unless they compared
slides stained with each side by side, which is how my students 
noticed the difference.

So - go wild. Try a different anionic red color!!!

Peggy A. Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073

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