[Histonet] Thawing brain tissue

[Maria Navas-Moreno]

Hello Histonet community,

I recently froze a primate brain using isopentane immerse in a bath of 100%
ethanol and chunks of dry ice. Two out of the 3 blocks froze fine but the
third one shows a very bad convex surface, although to be fair,
the defective block was embedded in gelatin while the other ones weren't.
We have had this issue before, even without the embedding, and my PI thinks
it could be due in part to a bad blocking procedure in which the surface is
not completely flat. Before we were able to "deal" with the convex defect.
This time it is so bad that we think it should be better to thaw and
re-freeze. When dealing with thawing is usually for other purposes (i.e.,
live cells retrieval) and I think it is suggested to thaw very fast, to
avoid water crystal issues. But in the case of morphology and IHC, will it
be beneficial to thaw quickly? I am trying to learn from others experience
so I can try so salvage this sample so any information is appreciated. I
know this is far from being a standard procedure but since the block got so
deformed I don't think there is any other option, I am just trying to find
the optimum conditions for a non-ideal situation.

Thanks

Maria Navas