title: Generation of functional eggs and sperm from cryopreserved whole testes.
abstract: The conservation of endangered fish is of critical importance. Cryobanking could provide an effective backup measure for use in conjunction with the conservation of natural populations; however, methodology for cryopreservation of fish eggs and embryos has not yet been developed. The present study established a methodology capable of deriving functional eggs and sperm from frozen type A spermatogonia (ASGs). Whole testes taken from rainbow trout were slowly frozen in a cryomedium, and the viability of ASGs within these testes did not decrease over a 728-d freezing period. Frozen-thawed ASGs that were intraperitoneally transplanted into sterile triploid hatchlings migrated toward, and were incorporated into, recipient genital ridges. Transplantability of ASGs did not decrease after as much as 939 d of cryopreservation. Nearly half of triploid recipients produced functional eggs or sperm derived from the frozen ASGs and displayed high fecundity. Fertilization of resultant gametes resulted in the successful production of normal, frozen ASG-derived offspring. Feasibility and simplicity of this methodology will call for an immediate application for real conservation of endangered wild salmonids.
authors: Department of Marine Biosciences,  Tokyo University of Marine Science and Technology, Tokyo 108-8477,  Japan.
authors: Seungki
authors: S
authors: Lee
authors: Yoshiko
authors: Y
authors: Iwasaki
authors: Shinya
authors: S
authors: Shikina
authors: Goro
authors: G
authors: Yoshizaki
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002454:Cell Differentiation; D002470:Cell Survival; D003247:Conservation of Natural Resources / Q000379:methods; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D005306:Fertilization; D005398:Fisheries / Q000379:methods; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008856:Microscopy, Fluorescence; D017686:Oncorhynchus mykiss / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010063:Ovum / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D013093:Spermatogonia / Q000166:cytology / Q000637:transplantation; D013094:Spermatozoa / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D013737:Testis / Q000166:cytology*; D057885:Triploidy
chemical_list: D049452:Green Fluorescent Proteins