[Histonet] Staining rabbit mast cells

[Ellen Liebenberg]

I am trying to identify mast cells in rabbit peripheral nerve.  The tissue 
is formalin fixed, postfiixed in osmium ( for myelin staining), and 
embedded in Technivit 7100.  I have tried a variety of acidic Toluidine 
blue, alcian blue, safranin O, and thionin protocols, as well as an 
alkaline thionin protocol from Bancroft, all of which are supposed to 
identify mast cells.  Areas of cartilage are staining as expected, but no 
mast cells.

I am looking in the highly vascular connective tissue around the median 
nerve.  Some of the specimens have been compressed and show myelin 
degeneration  and extensive cellular reaction.  Masts cells are probably 
present.  I plan to process rabbit skin as a control tissue, but have not 
got the tissue yet.

Could the osmium be interfering with staining? I have tried both non osmium 
stained gma and paraffin  sections and still did not see mast cells. Do 
rabbit mast cells stain differently from other species?  I plan to try the 
chloroacetate  esterase kit from Sigma, but it might not work with osmium.

Any suggestions would be greatly appreciated.

Ellen Liebenberg
University Califonia Medical Center
San Franscisco, Ca.