Cryopreservation of spermatogonial stem cells: an overview of cryoprotectants.

Spermatogonial stem cells (SSC) are adult stem cells within the testis that play an essential role in spermatogenesis and are critical for male fertility. SSC are highly susceptible to cancer treatments such as chemotherapy and radiotherapy, resulting in impaired spermatogenesis, which ultimately leads to subfertility or male infertility. In adults, freezing of sperm represents a mature and reliable method for fertility preservation. Considering the absence of mature spermatogonia in the testes of prepubertal children, SSC cryopreservation and transplantation may be an ideal approach for fertility preservation in prepubertal boys. However, conventional freezing techniques cause damage to SSC, reducing cell survival and affecting self-renewal and differentiation, and thus imposing a challenge for regeneration of spermatogenesis after transplantation. This review summarizes the effects of multiple cryoprotectants in SSC cryopreservation, providing ideas for optimizing SSC freezing techniques and facilitating the application of SSC cryopreservation in fertility preservation in prepubertal boys with cancer.