Abstract
To examine the spermatogenesis (and spermiogenesis) cell population kinetics after γ-irradiation, the frequency and fate of BrdU-labeled pre-meiotic spermatogenic cells (spermatogonia and pre-leptotene spermatocytes) and spermatogonial stem cells (SSCs) of the medaka fish (Oryzias latipes) were examined immunohistochemically and by BrdU-labeling. After 4.75 Gy of γ-irradiation, a statistically significant decrease in the frequency of BrdU-labeled cells was detected in the SSCs, but not in pre-meiotic spermatogenic cells. The time necessary for differentiation of surviving pre-meiotic spermatogenic cells without delay of germ cell development was shortened. More than 90% of surviving pre-meiotic spermatogenic cells differentiated into haploid cells within 5 days after irradiation, followed by a temporal spermatozoa exhaust in the testis. Next, spermatogenesis began in the surviving SSCs. However, the outcome was abnormal spermatozoa, indicating that accelerated maturation process led to morphological abnormalities. Moreover, 35% of the morphologically normal spermatozoa were dead at day 6. Based on these results, we suggest a reset system; after irradiation most surviving spermatogenic cells, except for the SSCs, are prematurely eliminated from the testis by spermatogenesis (and spermiogenesis) acceleration, and subsequent spermatogenesis begins with the surviving SSCs, a possible safeguard against male germ cell mutagenesis.
Original language | English |
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Pages (from-to) | 204-211 |
Number of pages | 8 |
Journal | Molecular Reproduction and Development |
Volume | 65 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2003 Jun 1 |
Keywords
- BrdU
- Cell cycle arrest
- Medaka fish
- Radiation
- Spermatogenesis
- Spermatogonial stem cells
ASJC Scopus subject areas
- Genetics
- Developmental Biology
- Cell Biology