neonatal mice brains shatters during cutting

[gaston]

I have 2 day old mice brains, which were not perfused, but placed in 4% para for about 18 hours, then in 18% sucrose for 10 days until cutting.  When attempting to cut at -20C in a cryostat after freezing in powdered dry ice, I could not get 1 single slice, because they all shatter into confetti.  Usually, if the brain is too cold (compared to cryostat temp), then shattering may occur, but this is not the case here. 

Any comments/suggestions would be appreciated.  thanks.

[szatmar]

Why don't you go with 10-20-30 sucrose. I have the impression that your samples got not really cryoprotected.

[elfrimml]

It is too cold.  Brains are cut at -14 on the block with the cryostat temp a little cooler.  Some times we even go a little warmer than that @ -12.