Regeneration of Spermatogenesis and Production of Functional Sperm by Grafting of Testicular Cell Aggregates in Zebrafish (Danio rerio)

Kawasaki, T., Saito, K., Shinya, M., Olsen, L.C., and Sakai, N.
Biology of reproduction   83(4): 533-539 (Journal)
Registered Authors
Sakai, Noriyoshi, Shinya, Minori
Sertoli cells, Spermatogenesis, Testis, spermatogonial stem cell, transplantation
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • Bromodeoxyuridine/metabolism
  • Immunohistochemistry
  • Male
  • Spermatogenesis/physiology
  • Spermatozoa/cytology
  • Spermatozoa/physiology*
  • Stem Cells/cytology
  • Stem Cells/physiology*
  • Testis/cytology
  • Testis/physiology
  • Testis/transplantation*
  • Zebrafish/physiology*
20554921 Full text @ Biol. Reprod.
The self-renewal and differentiation of spermatogonial stem cells (SSCs) is essential for the continuous production of sperm throughout life in male vertebrates. The development of a functional assay to analyze these properties in isolated SSCs remains essential. In our current study, we have developed a transplantation method for testicular cell aggregates in zebrafish in which allogeneic SSCs can undergo self-renewal and differentiation. The immature testes from juveniles are dissociated, aggregated by cultivation and then transplanted under the abdominal skin of the recipient fish. The grafted aggregates reconstitute the appropriate testicular structures including the lobule structure, consisting of basement membrane and interstitial steroid-producing cells on the outside, and the cysts, which comprise germ cell clusters and surrounding Sertoli cells. BrdU incorporation analysis indicated that continuous spermatogenesis is maintained at least for six months in the reconstituted testis. Moreover, when the sperm generated from the aggregates at three months post-grafting were used for artificial insemination, fertilized eggs were obtained that developed sexually mature fish. These results suggest that self-renewal of SSCs takes place in reconstituted testes under the abdominal skin and that their differentiating progeny can develop into functional sperm. Furthermore, allogeneic spermatogonia were also found to proliferate and differentiate into sperm in these grafts. Our method of grafting aggregates of testicular cells should thus prove useful for not only analyzing the stem cell ability of an individual SSC but also for the production of progeny from cultured SSCs or SSCs of sterile mutants in which spermatogenesis is affected non-germ cell autonomously.
Genes / Markers
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes