Effect of dose-rate on the survival of murine spermatogonia following 60Co gamma-irradiation.
The survival of murine clonogenic stem and differentiated spermatogonia was assessed by counts of repopulating tubules in histological sections at 35 days and counts of testicular sperm-heads at 29 days respectively, following irradiation delivered at five dose-rates (1.1, 2.5, 5, 11 and 112 Cgy X min-1). For stem spermatogonia, a significant increase in cell survival accompanied the reduction in dose-rate, and this was characterized by an increase of the Do for the derived survival curves from 2.86 +/- 0.29 Gy at 112 cGy X min-1 to 4.46 +/- 0.45 Gy at 1.1 cGy X min-1. The data were analysed using two mathematical models for repair at varying dose-rates, the LPL model of Curtis and the incomplete repair model of Thames. Using these models the half-time for repair was estimated to lie between 15 and 25 min. No dose-rate effects were observed for the differentiated spermatogonia. The sparing of stem spermatogonia at reduced dose-rate, may have implications for the future fertility of men treated with low dose-rate total body irradiation (TBI).
D000818:Animals; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D013093:Spermatogonia / Q000528:radiation effects*; D013094:Spermatozoa / Q000528:radiation effects*; D013234:Stem Cells / Q000528:radiation effects