We have excellent results using the following approach shipping brains between laboratories:

Fix in 4% PFA at least over night.

Trnasfer to 0.4% PFA for shipment at room temperature. This is just enough to maintain the tissue fixed and not too much to result in overfixation. We tried this technique on beta-gal and could actually still get decent beta-gal reaction after one week at 0.4% PFA at 4oC. We have used this technique now for over 10 years and never had a problem.

We do an antifreeze solution 300 g sucrose, 600 mL ethylene glycol + 1 L NaPhosphate buffer (0.05 M) and ship on small amounts of dry ice. Not too much dry ice because that will freeze the ethylene glycol (or avoid direct contact between the tubes and the dry ice).

We have excellent results using the following approach shipping brains between laboratories:

Fix in 4% PFA at least over night.

Trnasfer to 0.4% PFA for shipment at room temperature. This is just enough to maintain the tissue fixed and not too much to result in overfixation. We tried this technique on beta-gal and could actually still get decent beta-gal reaction after one week at 0.4% PFA at 4oC. We have used this technique now for over 10 years and never had a problem.

I second what Bernd said. Also, another mix that has worked well for us is a mixture of 30% sucrose and 4%PFA in equal parts (50/50). That is ok for room temp for a couple of days.

When we ship really long distance, like US - Europe, we only ship already frozen in OCT and then on dry ice. You need to be after the shipper to make sure they are fast AND maintain the dry ice, but it works.

If you have samples that are perfused with less % PFA or that cannot take any post fixation due to problems for your antibodies (ion channels for example), I would only ship fully frozen samples.

Good luck!

After the perfusion with 4% formaldehyde simply keep the brains in the same fixative during the transportation. I have done it and I did not have any problems with the tissue quality. In this way you can also transport brain slices, and then store them at -20 oC in a cryoprotectant (ethylene glycol) till the moment you need them (they are good even after 5-6 years)

I would like to suggest cryoprotective solutions other than 30% sucrose to avoid shrinkage. In my experience, best results were obtained using a solution made of 20% glycerin and 2% dimethylsulphoxide in 0.1 M PB, at neutral pH. Please take a look to the following paper: Rosene DL, Roy NJ, Davis BJ (1986). A cryoprotection method that facilitates cutting frozen sections of whole monkey brains for histological and histochemical processing without freesing artifact. J Histochem Cytochem 34: 1301-1316

We often ship cat brains from London, ON to Richmond, VA and have not had an issue (even in the middle of summer). During the perfusion, we rinse with 1L 0.01M PBS, then fix with 2L 4% PFA. We ship them in PBS and surround the brain with gauze to immobilize it and protect it from hitting the sides of the jar. Not sure if you are currently packing the brain with gauze, but that might be something to consider as well, that might affect the quality of your tissue.

We ship fixed mouse spinal cords from Australia to the UK on a regular basis for immunohistochemistry. We just fix in 4% PFA, wash in normal PBS, cryoprotect in 30% sucrose PBS, and ship in the same 30% sucrose PBS. Works every time. You could add some azide to the 30% sucrose PBS if you think there could be extended waiting periods. Good luck!

I usually post-fixed overnight in 4% PFA, then immersed the tissue in 30%sucrose/PBS. The tissue is safe in sucrose for extended periods of time, specially if the sucrose was sterile-filter upon preparation. I prefer to send the tissue in the sucrose because, if you freeze the tissue in OCT expedite delivery in dry-ice is a must. Sometimes, is not easy or affordable to warrant this. Also, people have different "maniacs" about how to set the tissue in the blocks or how quick they want the OCT to freeze (with dry ice only vs cyto-cool). If you send the tissue in sucrose, the person that is going to do the cutting could prepare the tissue embedding as he please. Many people appreciate that, at least I do.

Good luck!

Lillian

I receive numerous rodent brains from collaborators in Europe and elsewhere in the US and encourage them to leave the perfusion fixed brains in the skinned heads. To prevent over-fixation the suspending medium can be changed to PBS and the cranium opened slightly to allow some buffer exchange, but this does not seem to make a great deal of difference. It is important during shipping to avoid close proximity of the tubes containing the heads to freezer blocks as the slightest freezing can introduce artifacts.

We are doing lot of fixed human brain transport. You cannot ship formalin so the brain get removed from the formalin and put in a vacuum plastic bag and shipped room temperature. That worlds for us. Best. P

I agree with many points already said - personally, I'd avoid sending brains in 4% PFA with other additives, especially if overfixation for a few days can course immunoreaction problems. I'd ship in 30% sucroze in 0.1M PB with added either a small amount of fixative (1vol%), or (preferred by me) 0.02% sodium azide at lower temp (4C) using ice packs. Best. V.

After 4% PFA (20-24 H), cryoprotect in 10% sucrose (24H); 20% (24H);ship in 30% sucrose. Tissue is more even then when you place directly into 30% sucrose.