[Histonet] need a protocol for whole rat brain tissue processing

Geoff McAuliffe mcauliff <@t> umdnj.edu
Mon Nov 27 09:25:44 CST 2006

Hi Janice:

    You see what happens when you try to process an entire rat brain for 
paraffin embedding, the tissue is too thick to get good results. 
Reagents cannot penetrate in the time given.
1. Forget about immersion fixation of the whole rat brain if you want 
good morphology in the deeper parts of the brain, you will never get 
good results
because the fixative can't penetrate and preserve morphology before 
autolysis starts.
2. Even a brain well fixed by perfusion followed by immersion in 
fixative for a minimum of 48 hours (one week is much better for formalin 
fixation) can't be processed
whole as I mentioned above. Cut the brain into smaller pieces, 5-8 mm 
cross sections.
 3. If you insist on processing the brain whole you might look into 
embedding with nitrocellulose but this is very time-consuming and you 
will probably need a
sliding microtome to cut the brain.


Janice Ho wrote:

>I have some sample of rat brain which is not perfused with any fixitive before.
>The tissue is profixed in 4% paraformaldehyde for a week and then processed for
>paraffin section. But when the section is cut, it expands and breaks when float
>in water. Does anyone know why this happen and can give suggestion for the
>protocol? I also have rat brain when received 4% PFA perfucion before dissected
>out. These whole rat brain is profixed in fixitive overnight and then
>dehydrated with alcohol, again, after xylene and wex embedding, it breaks up
>when cut into 8 micron section. Does anyone can give me some suggestions on the
>protocol? Thanks a lot.
>Janice Ho
>University of Hong Kong
>Histonet mailing list
>Histonet <@t> lists.utsouthwestern.edu

Geoff McAuliffe, Ph.D.
Neuroscience and Cell Biology
Robert Wood Johnson Medical School
675 Hoes Lane, Piscataway, NJ 08854
voice: (732)-235-4583; fax: -4029 
mcauliff <@t> umdnj.edu

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