Your technique is the one first (I think) published by Lopez-De Leon A & Rojkind M (1985) A simple micromethod for collagen and total protein determination in formalin-fixed paraffin-embedded sections. J. Histochem. Cytochem. 33: 737-743. The photos in that paper show some of the collagen almost black - surely taking up both red and green dyes. More recent papers describe exactly the same method, and there are also some variants. Your technique, with an acid rinse after staining for an hour, then quick transition to rapid dehydration in 100% alcohol, is essential for any valid picro-sirius staining.
According to the entry for fast green FCF (CI 42053) in Conn's Biological Stains (10th ed, p.180-182), "chemically distinct blue-green dyes have been supplied under this name". Are you sure your fast green FCF is the real McCoy? Is it from a batch certified by the Biological Stain Commission? The jar of dye powder should have a small bluish label, with features that make forgery difficult. See https://biologicalstaincommission.org/certified-biological-dyesstains/ for pictures and other information. There are companies selling "certified stains" that have not been tested and certified by the Biological Stain Commission. Caveat emptor! The Biological Stain Commission is a not-for-profit corporation that has been providing third-party quality control and other services for vendors and users of stains for 100 years. Just a few thoughts; I could add more, but probably this letter already is too long for the Histonet censors. John Kiernan Professor Emeritus, Anatomy & Cell Biology University of Western Ontario, London, Canada https://www.schulich.uwo.ca/anatomy/people/bios/emeriti/kiernan_john.html Also Secretary, Biological Stain Commission, Inc. https://biologicalstaincommission.org = = = ________________________________ From: David Burk via Histonet <histonet@lists.utsouthwestern.edu> Sent: June 21, 2023 5:48 PM To: histonet@lists.utsouthwestern.edu <histonet@lists.utsouthwestern.edu> Subject: [Histonet] Fast Green / Sirius Red - Unknown blue features We are working out an alternative method for collagen staining using Fast Green / Sirius Red (Direct Red 80) rather than the standard picrosirius red method as I think it is prettier and easier to see the collagen on a green background. What we’ve noticed, though, is that we are seeing intermediate blue staining in the tissue in particular regions or structures. I’ve not had any success in finding an explanation for this online and was hoping someone on the board may have an idea of what’s going on and what is being stained blue in our tissue sections. We have examined a variety of murine or rat tissues including liver, heart, kidney, lung, skeletal muscle, spleen, brain, pancreas, and even decellularized human adipose tissue. There are, almost always, some structures/features that exhibit a denim blue to lighter blue-green color (at least to my eye) in addition to the expected red-colored structures that we would assume to be collagen, light green cytoplasm, and yellow-ish features stained with picric acid. An interesting tidbit is that these blue-ish stained features are birefringent under polarized light so you would not know their color (with transmitted imaging) was atypical. I don’t want to use a stain if I can’t let people know what a particular color represents and can also cause problems with the quantification of collagen using a color-based approach. Our protocol is as follows: 1. Dewax 2. H2O rinse 3. Stain in a 0.1% Fast Green FCF (C.I. 42053) and 0.1% Direct Red 80 (C.I. 35780) solution dissolved in saturated picric acid for 1 hour at room temperature 4. Dip 5x and then immerse in 0.5% acetic acid for 5 seconds 5. Repeat step 4 6. Dip 5x and then immerse in 100% Ethanol 30 seconds 7. Dehydrate in 100% Ethanol 1 min 8. Repeat step 7 9. 3 x Xylene for 2 min each 10. Coverslip I’m uploading some images from mouse muscle and tumor tissue to the Histonet Image upload site. If that doesn’t work, here are links: Mouse tumor: https://drive.google.com/file/d/1VjOZFzvsQByQLuDtdGPfdwAwap_CVE58/view?usp=sharing Mouse skeletal muscle: https://drive.google.com/file/d/10vT_FKu3-Ad5uemM5gnZmqDCKb3fs2lV/view?usp=sharing Thanks, David Burk _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet
