Rat testicle stem cells that were frozen for 23 years and then grafted onto infertile mice have been shown to produce viable sperm.
The possibility that pre-pubertal boys could freeze testicular tissue before cancer treatment that might affect their fertility so that it could be grafted on later and allow them to have children is being explored by scientists. This is similar to the ovarian tissue grafts that are offered to pre-pubertal girls who are not able to undergo egg collection before treatment.
While sperm can be collected and frozen prior to cancer treatment in adult males, this is not an option for pre-pubescent boys, who cannot yet produce sperm.
In this study, testicular stem cells taken from adult rats and frozen 23 years ago were reintroduced into infertile mice that had been treated with a drug that killed their sperm-making cells. Researchers also carried out the experiment with testicular cells frozen between one to four months ago and with fresh testicular cells. They found that just five to ten per cent of these long-term frozen cells were viable, but that after being implanted into mice did differentiate into viable sperm, albeit at a lower rate than fresh or briefly frozen cells. However, even the low sperm count is found to be encouraging if it works in humans who could undergo IVF. Read more.