[Histonet] Percent Sucrose for cryopreservation

[Pixley, Sarah (pixleysk)]

 Dear List:

What are the considerations in choosing the percent of sucrose for
cryopreservation for frozen sectioning? Here is what we are doing:
We perfuse mice with 4% peraformaldehyde in 0.1M phosphate buffer, then
fix overnight in the same. We dissect out either brain tissue or nose
tissue. The nasal tissues are decalcified with 10% formic acid, then
rinsed. All tissues are then immersed currently in 30% sucrose in 0.1M
phosphate buffer. We freeze in OCT compound using dry ice. Cryostat
sections are cut at 14-20 um, depending on the tissue. We then do
immunostaining for a variety of antigens, including BrdU. 

Our question is: Is 30% sucrose optimal or should we use a lower
percentage? We have heard that 30% may be too high. How would we
determine that?  We have not had any problems, so we are inclined of
course to let it go, but perhaps we could optimize it for this next
important set of experiments. 

Thanks,
Sarah Pixley