The induction of chromosomal damage and cell killing in mouse spermatogonial stem cells following combined treatments with hydroxyurea, 3-aminobenzamide and X-rays.
To analyze in more detail the relation between the sensitivity of spermatogonial stem cells to killing and the induction of genetic damage, mature male mice received combined treatments with hydroxyurea (HU), 3-amino-benzamide (3-AB) and X-rays. Stem cell killing was determined using the repopulation index method and translocations were studied via spermatocyte analysis. HU was administered at 16 or at 48 h before further treatment in order to create stem cell populations with different sensitivities in which the translocation induction and stem cell killing could be studied and compared. The sensitivities for cell death and genetic damage appeared to be strongly correlated: at 16 h after HU significantly higher values were found than at 48 h or in controls without HU pretreatment. By using 3-AB in the treatment schedules we were able to investigate whether the sensitization of stem cells towards cell death and genetic damage is the outcome of a radiation- or drug-induced G1 delay. The effect of 3-AB was most pronounced at 16 h after HU. This confirms that at this interval a large fraction of stem cells is in G1. Our data therefore indicate that all treatments that induce an enrichment of G1 cells also result in a sensitization of stem cells to cell killing or the induction of mutagenic damage.
van Buul
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MGC-Department of Radiation Genetics and Chemical Mutagenesis, State University of Leiden, Sylvius Laboratory, The Netherlands.
Bootsma
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D000818:Animals; D001549:Benzamides / Q000633:toxicity; D016923:Cell Death; D004260:DNA Repair / Q000187:drug effects; D016193:G1 Phase / Q000187:drug effects / Q000528:radiation effects; D006918:Hydroxyurea / Q000633:toxicity; D008297:Male; D051379:Mice; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000633:toxicity; D013093:Spermatogonia / Q000187:drug effects* / Q000528:radiation effects*; D014178:Translocation, Genetic
D001549:Benzamides; D011838:Radiation-Sensitizing Agents; C025160:3-aminobenzamide; D006918:Hydroxyurea