Testicular cryopreservation: From technical aspects to practical applications.

Testicular cryopreservation has been highlighted as a promising alternative for preserving male fertility and can be applied to restore spermatogenesis in prepubertal individuals or cancer patients, preserve biologically valuable genotypes, and in studies on reproductive physiology or toxicity of various substances. This review presents an analysis of the technical aspects and applications of testicular cryopreservation, examining the contributions of important studies in this area and discussing the different factors that can impact the efficiency of the technique. Testicular fragments can be obtained from living or dead individuals, at any age and reproductive stage, through orchiectomy or biopsy. Among the methods used for processing, slow freezing and vitrification in open or closed systems stand out. However, factors such as species, age, medium used, cryoprotectants, and cryopreservation method can influence the viability of the testis after heating. To obtain sperm, the testes can be cultured in vitro or in vivo and the recovered gametes applied in assisted reproduction techniques. However, in some species, mainly wild animals and humans, this is still a limitation to be overcome.