title: Birth of offspring following transplantation of cryopreserved immature testicular pieces and in-vitro microinsemination.
abstract: BACKGROUND
  Fertility protection is an urgent clinical problem for prepubertal male oncology patients who undergo either chemotherapy or radiotherapy. As these patients do not have mature sperm to be frozen, there is as yet no effective method to preserve their fertility.
  
  
  RESULTS
  Single pieces of immature mouse (1.5 x 1.5 x 1.5 mm) or rabbit (2.0 x 2.0 x approximately 3.0 mm) testis were cryopreserved, thawed and transplanted into mouse testes. Histological techniques were used to determine the presence of spermatogenesis, which was restored in both mouse and rabbit testicular pieces, and led to the production of mature sperm after both cryopreservation and syngeneic or xenogeneic transplantation into mouse testes. Using sperm developed in the frozen-thawed transplants, mouse offspring were born after in-vitro microinsemination. Furthermore, rabbit offspring were obtained using rabbit sperm that developed in fresh transplants in a xenogeneic surrogate mouse.
  
  
  CONCLUSIONS
  This approach of 'testicular tissue banking' is a promising technique for the preservation of fertility in prepubertal male oncology patients. Xenogeneic transplantation into immunodeficient mice may provide a system for studying spermatogenic failure in infertile men.
authors.affiliation: Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan. takashi@mfour.kyoto-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Shinohara
authors.forename: K
authors.initials: K
authors.lastname: Inoue
authors.forename: N
authors.initials: N
authors.lastname: Ogonuki
authors.forename: M
authors.initials: M
authors.lastname: Kanatsu-Shinohara
authors.forename: H
authors.initials: H
authors.lastname: Miki
authors.forename: K
authors.initials: K
authors.lastname: Nakata
authors.forename: M
authors.initials: M
authors.lastname: Kurome
authors.forename: H
authors.initials: H
authors.lastname: Nagashima
authors.forename: S
authors.initials: S
authors.lastname: Toyokuni
authors.forename: K
authors.initials: K
authors.lastname: Kogishi
authors.forename: T
authors.initials: T
authors.lastname: Honjo
authors.forename: A
authors.initials: A
authors.lastname: Ogura
mesh_terms: D000818:Animals; D015925:Cryopreservation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006358:Hot Temperature; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D008819:Mice, Nude; D008822:Mice, Transgenic; D011247:Pregnancy; D011817:Rabbits; D013091:Spermatogenesis; D013737:Testis / Q000254:growth & development / Q000637:transplantation*; D014015:Tissue Banks; D014183:Transplantation, Heterologous