Frozen sperm for 15 years still live

Sperm extracted from mice and testicles in the refrigerator for 15 years still produces healthy babies. The recent work of an international research group has opened up the hope of " rebirth " of extinct species.

The mice came from sperm of fathers in the refrigerator for 15 years.(Photo: BBC)

Currently, frozen sperm remains preserved in cryoprotectant - compounds that protect them from being destroyed from freezing. However, thawing process makes them not always conceive.

The team from Japan, England and Hawaii found that sperm will be safely hibernated for much longer, if it is kept in organs or the whole corpse and cooled slowly to minus 20 degrees. C or lower.

"Many people think that sperm's integrity can only last for a few months at most ., but in fact sperm cells maintain life much longer than our imagination", advanced. Dr. Atsuo Ogura from Japan's Riken Biological Resources Center said.

Freezing techniques here are also very simple. The mouse froze for 15 years just by putting it in a refrigerator usually at minus 20 degrees Celsius.

"This low temperature preservation technique may be the simplest way and everyone can do it. No need for liquid nitrogen. Any ordinary refrigerator or dry ice is working very well," Ogura to speak.

He also said this cryogenic technique could also be applied to many other mammals."Just put the testicles or corpse in the refrigerator."

However, he also noted that the corpses must be slowly cooled, in about 2-3 hours to reach minus 20 degrees Celsius. At lower temperatures it will be better preserved.

Further, Ogura said this step brought hope to restore extinct species, by taking sperm from male individuals found in permafrost, and injecting them into the eggs of the female close relatives.

T. An