title: Sperm preservation by freeze-drying for the conservation of wild animals.
abstract: Sperm preservation is a useful technique for the maintenance of biological resources in experimental and domestic animals, and in wild animals. A new preservation method has been developed that enables sperm to be stored for a long time in a refrigerator at 4 °C. Sperm are freeze-dried in a solution containing 10 mM Tris and 1 mM EDTA. Using this method, liquid nitrogen is not required for the storage and transportation of sperm. We demonstrate that chimpanzee, giraffe, jaguar, weasel and the long-haired rat sperm remain viable after freeze-drying. In all species, pronuclei were formed after the injection of freeze-dried sperm into the mouse oocytes. Although preliminary, these results may be useful for the future establishment of "freeze-drying zoo" to conserve wild animals.
authors.affiliation: Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Kaneko
authors.affiliation: Kyoto City Zoo, Kyoto, Japan; Wildlife Research Center of Kyoto University, Kyoto, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ito
authors.affiliation: Kyoto City Zoo, Kyoto, Japan; Wildlife Research Center of Kyoto University, Kyoto, Japan.
authors.forename: Hidefusa
authors.initials: H
authors.lastname: Sakamoto
authors.affiliation: Center for Environmental Biology and Ecosystem studies, National Institute for Environmental Studies, Ibaraki, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Onuma
authors.affiliation: Wildlife Research Center of Kyoto University, Kyoto, Japan; Center for Environmental Biology and Ecosystem studies, National Institute for Environmental Studies, Ibaraki, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Inoue-Murayama
mesh_terms: D000818:Animals; D000836:Animals, Zoo; D002470:Cell Survival; D005260:Female; D005612:Freeze Drying; D000068276:Giraffes; D008297:Male; D051379:Mice; D009865:Oocytes / Q000166:cytology / Q000254:growth & development; D002679:Pan troglodytes; D046009:Panthera; D051381:Rats; D012662:Semen Preservation / Q000379:methods*; D020554:Sperm Injections, Intracytoplasmic; D013094:Spermatozoa / Q000502:physiology*