Procedure that involves removing andfreezing the immature tissue of the testicle, followed by its implantation, led to the first birth of a living healthy monkey. This technique can theoretically help boys during the puberty period, who will receive cancer treatment: 30% of them become infertile due to the dramatic effects of chemotherapy and radiation. Currently, these boys have no choice that would allow them to guarantee biological children in the future.
Doctors can freeze adult spermmale patients, but boys start producing mature germ cells only when they reach puberty. At this point, hormonal changes in the body increase testosterone levels, stimulating the development of stem cells in the testicles into sperm. Chemotherapy and radiation therapy can deplete these stem cells, leading to low sperm and infertility.
Is it possible to freeze sperm in the testicles?
In a new study, scientists from the Medical SchoolThe University of Pittsburgh and its colleagues surgically removed and froze testicular tissue in five young rhesus monkeys that were too young to produce sperm. The macaques were then castrated to ensure that they were sterile. When the monkeys reached puberty, frozen tissues thawed and transplanted under the scrotum of the same animal from which they were originally taken.
After 8-12 months, scientists collected tissue fromtransplantation site and extracted sperm from it in the laboratory. The tissue produced enough sperm to fertilize 138 eggs. Of these, only 16 turned into embryos suitable for implantation. Researchers transferred 11 of these embryos to macaque females, which resulted in one pregnancy and subsequent live birth. The results of the work were published in Science.
"At the beginning of the experiment, we transplanted tissue withwhen sperm was harvested, they produced millions and millions of sperm, ”says Kyle Orvig, senior author and professor of obstetrics, gynecology and reproductive science at the University of Pittsburgh. "We are confident that if the same thing happens to human tissues, we will have more than enough sperm to fertilize an egg and conceive."
Regarding the low yield of embryos, Orvigsays that the procedure may have affected the quality of the sperm, and possibly other factors, such as testicle quality and reproduction time. Macaques usually breed from October to May. The first two experiments that Orvig and his team conducted were at the end and beginning of the breeding season, and no attempt resulted in a pregnancy. The third attempt in November 2017 led to the birth of a healthy female monkey in April last year.
Once again, animal experiments provide a chance for a healthier and more complete human life. Do you agree with this approach? Tell us in our chat.