ZFIN ID: ZDB-PUB-090407-9
Histological and Stereological Evaluation of Zebrafish (Danio rerio) Spermatogenesis with an Emphasis on Spermatogonial Generations
Leal, M.C., Cardoso, E.R., Nóbrega, R.H., Batlouni, S.R., Bogerd, J., França, L.R., and Schulz, R.W.
Date: 2009
Source: Biology of reproduction   81(1): 177-187 (Journal)
Registered Authors:
Keywords: Testis, Leydig cells, Sertoli cells, Spermatogenesis, teleost fish
MeSH Terms:
  • Animals
  • Cell Count
  • Cell Differentiation*
  • Germ Cells/cytology
  • Leydig Cells/cytology
  • Male
  • Models, Biological
  • Sertoli Cells/cytology
  • Spermatogenesis/physiology*
  • Spermatogonia/cytology
  • Spermatogonia/physiology*
  • Spermatogonia/ultrastructure
  • Testis/cytology
  • Testis/ultrastructure
  • Tight Junctions/physiology
  • Tight Junctions/ultrastructure
  • Zebrafish/anatomy & histology*
  • Zebrafish/growth & development
PubMed: 19339708 Full text @ Biol. Reprod.
The zebrafish has become an important vertebrate model for basic and biomedical research including the research field of biology of reproduction. However, very few morphological and stereological data are available as regards zebrafish testis structure and spermatogenesis. In this careful histomorphometric evaluation of the testis, we studied spermatogonial cells using molecular markers, determined the combined duration of meiotic and spermiogenic phases, and examined the formation of the Sertoli cell barrier (tight junctions). We found at least 9 spermatogonial generations and propose a morphology-based nomenclature for spermatogonial generations that is compatible with the one used in higher vertebrates. The number of germ cells per cyst increased dramatically (1 to ~1360 cells) from undifferentiated spermatogonia type A to early spermatids. The combined duration of meiotic and spermiogenic phases is approximately 6 days, one of the shorter ones among the teleost fish investigated to date. The number of Sertoli cells per cyst increased 9-fold during the maturational cycle of spermatogenic cysts and stabilized in the meiotic phase at a ratio of approximately 100 early spermatids per Sertoli cell (Sertoli cell efficiency). Similar to mammals, Sertoli cell proliferation ceased in the meiotic phase, coinciding with the formation of tight junctions between Sertoli cells. Hence, the events taking place during puberty in the germinal epithelium of mammals seem to recapitulate the "life history" of each individual spermatogenic cyst in zebrafish.