I understand that perfusion is good for getting good histological analyses of adult mouse brains, but what about pups? Let's say below 4 weeks. Do they still need to be perfused? Thanks!
For tissue preservation the cardiac perfusion is the best. I have done perfusions to as low as 1 week postnatal. And pups younger than that (Embryonic to P7) I do dissect the brains out under stereomicroscope in ice-cold physiological extracellular solution as described in my methods paper below. And than try to peel of the brain membranes (meninges) off, cut the brain into several pieces and incubate in 4%PFA for 3-5 hours in the fridge. After that you can wash in PBS and do your sucrose treatment if you are going to do cryosectioning.
best wishes, Refik
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Pups will be too small to be perfused. Brains are not yet myelinated. Fix by immersion with 4 % PFA and post-fix on Bouin solution or 10% formaldehyde. Bouin solution can be obtained commercially or prepared with picric acid. Several recipe are available on line or in a basic histotechnoly book. Brains can be fixed in situ after opening skull. The least manipulation before fixation as it is easy to induce artefacts that will interfere with the histopathology interpretation
We had some problems isolating the brain of one of our KO lines because they were so soft to cut. We solved the problem perfusing pregnant females at 18.5 days and isolating the brain of the pups afterwards.