title: Induction of a cytogenetic adaptive response in germ cells of irradiated mice with very low-dose rate of chronic gamma-irradiation and its biological influence on radiation-induced DNA or chromosomal damage and cell killing in their male offspring.
abstract: In earlier studies we have shown that either a single exposure or multiple exposures to a low dose of X-rays (0.05 Gy) induced a significant cytogenetic adaptive response in mouse germ cells. In this paper, a very low-dose rate (20 microGy/min) of chronic 60Co gamma-irradiation was used to pre-irradiate mice for 40 days. Then, another 40 days later, these mice were treated with a subsequent large dose of X-irradiation, followed 24 h later by cytogenetic analysis of their spermatocytes. Analysis for radiation-induced DNA and chromosomal damage was also carried out in splenocytes, bone marrow cells and spermatocytes of the offspring of mice adapted by the low-dose rate of chronic gamma-irradiation. Results demonstrated that (i) cumulative gamma-irradiation (1.10 Gy) at the dose rate 20 microGy/min induced a marked cytogenetic adaptive response in the mouse germ cells (stem spermatogonia); (ii) the sensitivity of offspring's bone marrow cells and spermatocytes to 1.5 Gy X-ray-induced chromosome aberrations was not influenced by the low-dose radiation delivered to paternal germ cells; (iii) either constitutive or post-irradiation DNA repair capacity (UV-induced unscheduled DNA synthesis, UDS) was not modified in the offspring's splenocytes; (iv) the sensitivity of the offspring's splenocytes to radiation-induced cell killing was also not altered. These results suggest that low-dose radiation delivered to the male parents with a significant induction of cytogenetic adaptive response in their germ cell does not likely cause any risk of damaging effects to the offspring of those irradiated male mice.
authors.affiliation: Institute of Radiation Medicine, Norman Bethune University of Medical Sciences, Changchun, People's Republic of China.
authors.forename: L
authors.initials: L
authors.lastname: Cai
authors.forename: P
authors.initials: P
authors.lastname: Wang
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics* / Q000528:radiation effects; D000818:Animals; D001853:Bone Marrow / Q000502:physiology / Q000528:radiation effects; D001854:Bone Marrow Cells; D016923:Cell Death / Q000528:radiation effects*; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects*; D003582:Cytogenetics; D004247:DNA / Q000096:biosynthesis; D004249:DNA Damage / Q000528:radiation effects*; D004260:DNA Repair / Q000528:radiation effects; D005260:Female; D005720:Gamma Rays; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009152:Mutagenicity Tests; D018812:Paternal Exposure; D011247:Pregnancy; D011829:Radiation Dosage; D013094:Spermatozoa / Q000502:physiology* / Q000528:radiation effects*; D013154:Spleen / Q000166:cytology / Q000528:radiation effects; D013997:Time Factors; D014466:Ultraviolet Rays; D014916:Whole-Body Irradiation; D014965:X-Rays
chemical_list: D004247:DNA