Changes in gene expression profiles in mouse liver induced by long-term low-dose-rate γ irradiation were examined by microarray analysis. Three groups of male C57BL/6J mice were exposed to whole-body radiation at dose rates of 17–20 mGy/day, 0.86–1.0 mGy/day or 0.042–0.050 mGy/day for 401–485 days with cumulative doses of approximately 8 Gy, 0.4 Gy or 0.02 Gy, respectively. The gene expression levels in the livers of six animals from each exposure group were compared individually with that of pooled sham-irradiated animals. Some genes revealed a large variation in expression levels among individuals within each group, and the number of genes showing common changes in individuals from each group was limited: 20 and 11 genes showed more than 1.5-fold modulation with 17–20 mGy/day and 0.86–1.0 mGy/day, respectively. Three genes showed more than 1.5-fold modulation even at the lowest dose-rate of 0.04–0.05 mGy/day. Most of these genes were down-regulated. RT-PCR analysis confirmed the expression profiles of the majority of these genes. The results indicate that a few genes are modulated in response to very low-dose-rate irradiation. The functional analysis suggests that these genes may influence many processes, including obesity and tumorigenesis.
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30 August 2010
Gene Expression Profiles in Mouse Liver after Long-Term Low-Dose-Rate Irradiation with Gamma Rays
Yoshihiko Uehara,
Yasuko Ito,
Keiko Taki,
Mitsuru Nenoi,
Kazuaki Ichinohe,
Shingo Nakamura,
Satoshi Tanaka,
Yoichi Oghiso,
Kimio Tanaka,
Tsuneya Matsumoto,
Tatjana Paunesku,
Gayle E. Woloschak,
Tetsuya Ono
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Radiation Research
Vol. 174 • No. 5
November 2010
Vol. 174 • No. 5
November 2010