Frequencies of Chromosome Aberrations are Lower in Splenic Lymphocytes from Mice Continuously Exposed to Very Low-Dose-Rate Gamma Rays Compared with Non-Irradiated Control Mice

Atsushi Kohda; Takuo Toyokawa; Tomoyuki Umino; Yoshiko Ayabe; Ignacia Braga Tanaka; Jun-Ichiro Komura

doi:10.1667/RADE-21-00159.1

Frequencies of Chromosome Aberrations are Lower in Splenic Lymphocytes from Mice Continuously Exposed to Very Low-Dose-Rate Gamma Rays Compared with Non-Irradiated Control Mice

Radiat Res. 2022 Oct 21. doi: 10.1667/RADE-21-00159.1. Online ahead of print.

Authors

Atsushi Kohda¹, Takuo Toyokawa², Tomoyuki Umino², Yoshiko Ayabe³, Ignacia Braga Tanaka¹, Jun-Ichiro Komura¹

Affiliations

¹ Department of Radiobiology, Institute for Environmental Sciences (IES), 2-121 Hacchazawa, Takahoko, Rokkasho, Kamikita, Aomori 039-3213, Japan.
² Tohoku Nuclear Co., Ltd., 2-41-14 Higashi Okamisawa, Misawa, Aomori 033-0024, Japan.
³ Tohoku Research Center, Forestry and Forest Product Research Institute, 92-25 Nabeyashiki, Shimo-Kuriyagawa, Morioka, Iwate 020-0123, Japan.

PMID: 36270025
DOI: 10.1667/RADE-21-00159.1

Abstract

Chromosome aberrations have been one of the most sensitive and reliable biomarkers of exposure to ionizing radiation. Using the multiplex fluorescence in situ hybridization (M-FISH) technique, we compared the changes, over time, in the frequencies of translocations and of dicentric chromosomes in the splenic lymphocytes from specific pathogen-free (SPF) C3H/HeN female mice continuously exposed to 0.05 mGy/day (18.25 mGy/year) gamma rays for 125 to 700 days (total accumulated doses: 6.25-35 mGy) compare with age-matched non-irradiated controls. Results show that the frequencies of translocations and of dicentric chromosomes increased significantly over time in both irradiated and non-irradiated control mice, and that the frequencies were significantly lower, not higher, in the irradiated mice, which differs from our previous reports of increased chromosome aberration frequencies at higher radiation dose rates of 1 mGy/day and 20 mGy/day. These results will be useful when considering the radiation risk at very low-dose rates comparable to regulatory dose limits.