WuXi AppTec Content Team Editor
Even in a laboratory where living conditions are good, rats typically live only about three years. However, Cryopreservation of testicular tissue from male rats, more than two decades later, these rats still have the opportunity to produce offspring with their own sperm. Recently, researchers at the University of Pennsylvania’s School of Veterinary Medicine published the results of such an experiment.
▲Research paper published in the open access journal PLOS Biology
The researchers thawed rat testicular tissue that had been frozen in the laboratory for at least 23 years and isolated spermatogonial stem cells (SCC). Spermatogonial stem cells are like the “seeds” of sperm and are the basis of male reproduction, and normally differentiate into all germ cell types, including mature sperm.
In this experiment, the researchers demonstrated that transplanting spermatogonial stem cells that had been cryopreserved for more than two decades into infertile male mice resulted in no immune rejection. (the experiments used so-called “nude mice,” animals lacking an immune response), they could still differentiate as they should with various germ cell types, including viable sperm.
▲Testicular tissue sections from sterile mice showing that cryopreserved tissue differentiated to produce germ cells and sperm after transplantation (Image source: Reference data[1])
Of course, the ability of these spermatogonial stem cells to be cryopreserved for such a long period of time will be affected to produce live sperm. The experiment also transplanted freshly isolated and frozen testicular tissues that had only been cryopreserved for a few months. In contrast, long-term cryopreserved spermatogonial stem cells had lower transplant success rates and produced fewer sperm cells.
Furthermore, although long-term cryopreserved spermatogonial stem cells were similar to short-term cryopreserved cells in terms of changes in gene expression, sperm cells differentiated after transplantation were Long sperm count is low.
▲Cryopreserved germ cells are transplanted into animals and differentiated to produce spermThe process of sperm (Image source: Reference [1])
In fact, scientists wanted to see how long testicular tissue in rats could continue to produce functional sperm after cryopreservation, not for curiosity, but to hope these results. Can help boys with cancer.
Over the past few decades, the treatment of childhood cancer has become increasingly successful, allowing many children who are unfortunately born with cancer to be reborn. However, for boys approaching puberty, a serious side effect of chemotherapy is the potential to affect future fertility, leading to subfertility or infertility in adulthood.
In order to preserve the fertility of these children, there is currently a strategy of taking a portion of the testicular biopsy containing stem cells and cryopreserving it for future use prior to chemotherapy. With the technology available, they can eventually re-implant their own spermatogonial stem cells into the body to make sperm.
