Spermatogonial Stem Cell Transplantation and Culture

Abstract

The study of spermatogonial stem cells (SSCs) has been hampered by the lack of techniques to identify, quantify, and maintain these cells both in vitro and in vivo. Although markers to definitively identify a specific cell as a SSC are still unknown, techniques to maintain SSCs in vitro and to quantify the number of SSCs in a specific cell population have been developed. SSC transplantation is a technique in which a population of cells is transplanted into the testis of a recipient. Presence of SSCs within the transplanted cells can later be validated by the production of donor-derived colonies of spermatogenesis within the recipient testis. This technique is extremely valuable for the quantitative analysis of the effect of experimental treatments on SSC numbers as well as the generation of donor-derived and transgenic spermatozoa for biotechnological applications. In vitro SSC culture has allowed for a platform to study mechanisms regulating SSC function outside of the testis, and when combined with SSC transplantation, serves as a powerful tool to study these cells. The development of SSC transplantation and culture techniques has revolutionized the study of these important cells; however, care must be taken when interpreting data using these techniques due to the absence of a definitive SSC marker. Nevertheless, many recent advances using these techniques, including SSC transplantation in livestock and companion animals and the elucidation of the roles of growth factors in SSC function, have significantly advanced the field of SSC biology.