title: Spermatozoa and spermatids retrieved from frozen reproductive organs or frozen whole bodies of male mice can produce normal offspring.
abstract: Cryopreservation of male germ cells is a strategy to conserve animal species and strains of animals valuable to biomedical research. We tested whether mouse male germ cells could be cryopreserved without cryoprotection by simply freezing epididymides, testes, or whole bodies. The reproductive organs were isolated from killed mice and frozen for 1 week to 1 year at -80 degrees C before spermatozoa and spermatids were collected and injected into mature oocytes. Normal pups were born irrespective of strains tested (ICR and C57BL/6). Epididymides and testes frozen and transported internationally to another laboratory by air could produce pups of inbred C57BL/6 mice. Testicular spermatozoa retrieved from the bodies of male mice (BALB/c nude and C3H/He strains) that had been kept frozen (-20 degrees C) for 15 years could also produce normal offspring by microinsemination. Thus, freezing of either male reproductive organs or whole bodies is the simplest way to preserve male germ cells. Restoration of extinct species could be possible if male individuals are found in permafrost.
authors.affiliation: Institute of Physical and Chemical Research RIKEN Bioresource Center, Tsukuba, Ibaraki 305-0074, Japan.
authors.forename: Narumi
authors.initials: N
authors.lastname: Ogonuki
authors.forename: Keiji
authors.initials: K
authors.lastname: Mochida
authors.forename: Hiromi
authors.initials: H
authors.lastname: Miki
authors.forename: Kimiko
authors.initials: K
authors.lastname: Inoue
authors.forename: Martin
authors.initials: M
authors.lastname: Fray
authors.forename: Takamasa
authors.initials: T
authors.lastname: Iwaki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Moriwaki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Obata
authors.forename: Kazuto
authors.initials: K
authors.lastname: Morozumi
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Yanagimachi
authors.forename: Atsuo
authors.initials: A
authors.lastname: Ogura
mesh_terms: D000818:Animals; D015925:Cryopreservation; D004622:Embryo, Mammalian / Q000196:embryology; D004822:Epididymis / Q000378:metabolism; D005260:Female; D005307:Fertilization in Vitro; D005615:Freezing; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009865:Oocytes / Q000378:metabolism; D012098:Reproduction / Q000502:physiology*; D013048:Specimen Handling; D013087:Spermatids / Q000166:cytology / Q000502:physiology*; D013696:Temperature; D013737:Testis / Q000166:cytology; D013997:Time Factors