Open AccessRadiation sensitivity and genomic instability in the hematopoietic system: Frequencies of micronucleated reticulocytes in whole‐body X‐irradiated BALB/c and C57BL/6 mice
Author(s) -
Hamasaki Kanya,
Imai Kazue,
Hayashi Tomonori,
Nakachi Kei,
Kusunoki Yoichiro
Publication year - 2007
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2007.00641.x
Subject(s) - haematopoiesis , bone marrow , irradiation , genome instability , balb/c , whole body irradiation , cancer research , immunology , biology , medicine , genetics , dna , physics , stem cell , immune system , dna damage , nuclear physics
Using flow cytometry, we quantified the number of micronucleated reticulocytes in peripheral blood of whole‐body X‐irradiated mice in order to evaluate the radiation sensitivity and the induced genomic instability of the hematopoietic system. An acute effect of radiation dose as small as 0.1 Gy was detectable 2 days after irradiation, and the radiation dose effect was significantly greater in BALB/c mice than in C57BL/6 mice, that is, 3.0‐ and 2.3‐fold increases in frequencies of micronuclei were noted in the two groups of mice, respectively. Even 1 year after irradiation, mice irradiated with 2.5 Gy of X‐rays showed significantly increased frequencies of micronucleated reticulocytes, that is, 1.6‐ and 1.3‐fold increases in BALB/c and C57BL/6 mice, respectively. However, this delayed effect was not apparent when the same mice were analyzed for T‐cell receptor mutant frequencies in splenocytes. A significant mouse strain difference in the delayed radiation effect on micronucleated reticulocyte frequencies was noted as well. The results indicate that delayed genomic effects of irradiation on the murine hematopoietic system can persist in vivo for prolonged periods, and that there are mouse strain differences in sensitivity to radiation‐induced genomic instability. ( Cancer Sci 2007; 98: 1840–1844)