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Mcnamara, George wrote:

> "To decrease background immunofluorescence and autofluorescence of
> hemoglobin, the tissue sections were pretreated with 0.1% sodium borohydride
> in PBS (30min), followed by 1-5min incubation in 0.5% Sudan black in 70%
> ethanol."
> Casella GT
>
> The above is closely related to:
> "We found that 1-10 mM CuSO4 in 50 mM ammonium acetate buffer (pH 5) or 1%
> Sudan Black B (SB) in 70% ethanol reduced or eliminated lipofuscin
> autofluorescence in sections of monkey, human, or rat neural tissue."
> Schnell SA

The trick with Sudan Black would be expected to quench the fluorescence
of any lipophilic compartment, so it might or might not interfere with
specific staining as well.  CuSO4 is something that works only for
lipofuscin, as far as we know.  NaBH4 would reduce double bonds which
might decrease autofluorescence, depending on the chemistry of the
autofluorescent molecule.

I don't know anything of the underlying source of the autofluorescence
you see in RBCs.  I have never noticed it in many years of looking at
rat tissue (including some with blood in it).  I wonder if it's due to
overly long fixation (or perhaps fixation with glutaraldehyde).  If so,
  NaBH4 should help.

Good luck!

Martin Wessendorf

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