RE: sectioning of frozen tissues

From:"C.M. van der Loos"

Dear all,
So far I have never observed any epitopes/antigens that did not survive 
an overnight drying at room temperature. There are drying protocols out 
there that tell you to dry in a stove at 37C or even 50C! Although 
this sounds as a very harsh procedure for very effective drying of the 
cryostat tissue section, most epitopes/antigens can stand it easily.

Chris van der Loos
Academic Medical Center H0-120
Dept. Cardiovascular Pathology
Meibergdreef 9
NL-1105 AZ Amsterdam

>Date: 18 Dec 2002 14:45:44 -0600
>Subject: sectioning of frozen tissues
>Greetings histology experts,
>   We are doing immunohistochemistry on frozen sections but so many
>times the morphology of the sections (especially small tissues such as
>mouse thymus) are terrible.  Consequently we've been looking for
>alternative protocols.  We are considering the protocol listed on the
>Pharmigen web site.  Part of the protocol is as follows:
>II. Sectioning of Frozen Tissues
>         1.Before cutting sections, allow the temperature of the block
>to equilibrate to the temperature of the cryostat (-20#176#C).
>         2.Place the tissue block on the cryostat specimen disk. Adjust
>the positioning of the block to align the block with the knife blade.
>Cut tissue block until the desired tissue is exposed.
>         3.Cut sections of the desired thickness (usually 5 um), place
>the sections on a Fisher Superfrost slide and dry overnight at room
>         4.Fix slides by immersion in cold acetone (-20#176#C) for 2
>minutes or other suitable fixative (e.g. alcohol, formal alcohol,
>formalin, etc.), air dry at room temperature and proceed to staining
>(Section III).
>         5.Alternatively, the frozen section slides can be stored for a
>short period of time at -70#176#C in a sealed slide box. When ready to
>stain, remove
>          slides from freezer and warm to -20#176#C in the cryostat or
>- -20#176# freezer, fix for 2 minutes in cold fixative (acetone or=20
>suitable fixative)
>            and allow to come to room temperature to continue with the
>    Now, my question is wouldn't allowing the section to dry overnight
>at room temperature (as described in step 3) result in destruction of
>certain proteins (maybe ones we want to stain for)?
>Thank you in advance,
>Dale Osborne
>Washington University School of Medicine
>Anesthesiology Dept.
>St. Louis, MO


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