受精ジャーナル:体外受精 - 体外受精 - 世界中、生殖医学、遺伝学、幹細胞生物学
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概要

What contributes to the success of in vitro fertilization using cryopreserved spermatozoa in rodents?

Junya Ito

In 1963, Yanagimachi and Chang first succeeded in fertilizing golden hamster eggs in vitro without any contributions from the female genital tract [1]. This is the first success of 'In Vitro Fertilization (IVF)' in mammals. After this success, the protocol of IVF has been established in most of mammalian species studied up to date. At last, the Nobel Prize in Physiology or Medicine 2010 was awarded to Dr. Robert G. Edwards who reported the first success of IVF in human with Dr. Patrick C. Steptoe [2]. Also in experimental animals, IVF is a powerful tool for production of offspring. Alternatively, intracytoplasmic sperm injection (ICSI) is now available for the purpose; however, ICSI requires a great deal of skill and cannot be used for many oocytes at the same time. Thus, especially in the production of rodent offspring at the facility, IVF is a more simple and general-purpose method. Moreover using frozen-thawed spermatozoa for IVF can decrease the number of males to be sacrificed for collection of epididymal spermatozoa. However, it has been reported that frozen-thawed spermatozoa from several strains even in mice contribute to low fertility after IVF. Since fresh sperm can fertilize to the oocytes, the process during freezing and thawing seems to affect serious damage of the sperm. Recently, some recent reports have demonstrated significant improvement of IVF using cryopreserved sperm.