Did someone once revived after cryopreservation?
This is a question often asked, but that does not make it more clear.
The fact that the cooling and freezing / thawing biological organisms occurs quite differently and with different results. It depends on what the body is seen (or body), as well as on - the temperature to which cools the body and for some technologies.
For example, many small organisms without the use of any cryobiological technologies themselves can endure staying in liquid nitrogen, and even in outer space. Such, for example tardigrades (tardigrady) leech species Ozobranchus jantseanus, the nematode worm (in this case, we shall deal separately below).
Other small animals can withstand freezing - to different temperatures - after the application of special techniques. For example, in 2012. The team of scientists under the leadership of Vladimir Koshtan (Vladimir Kostal) South Bohemian University in Ceske Budejovice (Czech Republic) was able to successfully freeze and restore the lives of several larvae of flies, fruit flies (Drosophila melanogaster), who can not tolerate cold in nature.
Well, scientists are able to freeze / unfreeze the different cells of the body (eg, sperm), fish eggs, part of the ovarian tissue, blood vessels. Some of these procedures have become part of the medical and scientific practice.
It is also widely known that there are some animals that spontaneously hibernate, for example, most invertebrates, reptiles, amphibians, some species of fish, birds (nightjars), many species of rodents, insectivores (hedgehogs), bats, edentates and other mammals, including some primates (lemurs).
But reversible freezing technology to very low (they are called cryogenic) temperatures, and large bodies of organisms has not yet been given to scientists. While here in the last decade, there is progress.
First of all, I must say, a reversible freeze in 2005, Cryobiology most famous rabbit kidney Gregory Fey from the company 21st Century Medicine (US). Later it was a very high quality frozen (not thawed) pig liver - the company Arigos Biomedical, USA. In early 2016 it became known that besides the United States rabbit brain successfully frozen and thawed without damaging nerve cells.
The rabbit was injected brain glutaraldehyde, after which the body for four hours cooled to -130 degrees simultaneously injected liquid cryoprotectant. When defrosting the researchers slowly heated brain, and then removed the cryoprotectant.
The authors explain that as a result of the gradual freezing and careful thawing is not damaged any synapse. Preservation of brain tissue before and after treatment were analyzed by electron microscopy.
Nevertheless, it is possible to judge how fairly - neither relatively large warm-blooded animals was not yet frozen reversible. This prevents the complexity of the process: the freezing of large biological objects manifest physical and chemical factors, the negative impact of which is not relevant to cryopreservation (cryopreservation, freezing) of small objects such as cells or microorganisms.
Despite this, scientists - as we see it - confidently moving along the path of the reversible cryopreservation increasingly large biological organisms. We hope that will be the apotheosis of Cryobiology reversible freezing of humans and large animals. At least, until now there has been no fundamental law of nature, which would forbid it.