[Histonet] sirius red

[Y. Wang]

Dear all,

I have a question regarding sirius red staining.

Background: We are looking at amino acid based polyurethane 'mesh' 
(fibrous structure) that are unseeded or seeded with porcine mitral valve 
cells. The seeded scaffolds were either loaded or unloaded. We are 
investigating the collagen production (we have used a pro-collagen assay 
as well as a hydroxyproline assay and have come up with positive results). 
In the past we have used Massons Trichrome to get some pretty pictures, 
however, even using the room temperature mordent (overnight) was not good 
for the polymer (biodegradable) so we have started to use sirius red 
staining (thank you to the histonet members for the protocols we found on 
the archives!)

Sections: samples were embedded in OCT. 5um sections were taken to be 
stained.

There is one sample that we see staining (reddish)under bright-field and 
polarized light (we are assuming this is collagen). For the majority of 
the seeded scaffolds we are seeing 'cell-like' red staining which does not 
show under polarized light (cytoplasm?). However, with the unseeded 
controls we see similar (although not really cell-like) staining which is 
predominently at/near the sample-OCT interface. Does anyone have any ideas 
as to what it would be? I was thinking it could possibly be trapped dye 
where the section has folded in slightly? The scaffold itself is staining 
slightly pink too.

Thanks for your help

Yak-Nam Wang

Senior Fellow
Department of Bioengineering
University of Washington
Seattle, WA 98195