[Histonet] Thawing brain tissue

[Maria De Los Angeles Navas]

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