[Advances in researches on cryopreservation of testicular spermatozoa]

Infertility affects approximately 20% of childbearing couples in the world, and azoospermia accounts for 10－15% of the causes of male infertility. The use of fresh or frozen-thawed testicular sperm for intracytoplasmic sperm injection (ICSI) has become a main method for azoospermia patients to realize their dream for reproduction. However, testicular spermatozoa are not further matured in the epididymis and therefore have an obviously lower anti-freezing ability than ejaculated sperm. The viability and retrieval rate of sperm are low after freeze-thaw with the conventional method of cryopreservation. Since the first live birth with frozen-thawed testicular spermatozoa, continuous improvement has been made in the methods of testicular sperm cryopreservation and increased the viability and retrieval rate of spermatozoa after freeze-thaw. This review focuses on the methods of testicular sperm cryopreservation in the past 20 years to provide a theoretical basis for the development of assisted reproductive technology.