Induction of cytogenetic adaptive response of somatic and germ cells in vivo and in vitro by low-dose X-irradiation.
The cytogenetic adaptive response induced by low-level radiation was studied using human and rabbit lymphocytes in vitro and bone marrow cells and germ cells in vivo. The inductive dose of X-rays was 10 mGy for the in vitro studies at a dose rate of 10 mGy/min, and 2, 10, 50, 75 and 100 mGy for the in vivo studies at a dose rate of 50 mGy/min. The challenging dose was 1.5 Gy X-rays for the in vitro experiments and 0.65 or 0.75 Gy for the in vivo experiments at a dose rate of 0.44 Gy/min. The results reported here, in addition to those that have appeared in the literature, show the following characteristics documented for the first time: (1) 10 mGy could induce the adaptive response in human as well as rabbit lymphocytes irradiated not only in G1, S and G2 phases, but also in the Go state; (2) although the induced adaptive response could only last three cell cycles, it could be revived when the inductive dose was repeated after the third cell cycle; (3) the adaptive response could be induced by low-dose X-rays in somatic cells, both in vitro (lymphocytes) and in vivo (bone marrow cells), and also in germ cells (spermatocytes); (4) the magnitude of the adaptive response induced by whole-body irradiation was found to be dose-dependent--the lower the inductive dose the more the reduction of the frequency of chromatid aberrations following the challenging dose.
Cai
L
L
Department of Radiation Biology, Norman Bethune University of Medical Sciences, Changchun, China.
Liu
S Z
SZ
D000220:Adaptation, Biological / Q000235:genetics* / Q000528:radiation effects; D000818:Animals; D001853:Bone Marrow / Q000502:physiology / Q000528:radiation effects*; D001854:Bone Marrow Cells; D002453:Cell Cycle / Q000502:physiology; D002869:Chromosome Aberrations / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000502:physiology / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011817:Rabbits; D011831:Radiation Genetics; D013090:Spermatocytes / Q000502:physiology / Q000528:radiation effects*