Presentation Effects from chronic restraint-induced stress on radiation-induced chromosomal aberrations in mouse splenocytes

勝部, 孝則  ,  Bing, Wang  ,  Tanaka, Kaoru  ,  Ninomiya, Yasuharu  ,  Vares, Guillaume  ,  劉強  ,  森田明典  ,  Nakajima, Tetsuo  ,  Nenoi, Mitsuru

Exposure to either ionizing radiation (IR) or psychological stress (PS) could cause detrimental effects on humans. A recent study showed that chronic restraint induced PS (CRIPS) could attenuate Trp53 functions and increase radiocarcinogenesis in Trp53-heterozygous mice, having a big impact on the academic and a sensational effect on the public, especially the residents living in the radioactively contaminated areas. To elucidate possible modification effects from CRIPS on radiation-induced health consequences in Trp53 wild type (Trp53wt) animals, a series of investigation with multidisciplinary analyses was done. We demonstrate here the changes in frequency of chromosomal aberrations (CAs) in splenocytes. Five-week-old male Trp53wt C57BL/6J mice were restrained 6 hours per day for consecutive 28 days, and total-body irradiation (TBI) at a dose of 4 Gy was given on the 8th day. Metaphase chromosome spreads prepared from splenocytes at the end of the 28-day restraint regimen were painted with the fluorescence in situ hybridization (FISH) probes for chromosomes 1 (green), 2 (red) and 3 (yellow). Results showed that CRIPS alone did not induce CAs, while TBIcaused significant increase of CAs, mostly stable types (translocations and insertions). Intriguingly, the stable-type CAs appeared at a little high frequency in mice exposed to TBI plus CRIPS than those in mice exposed to TBI alone. Whereas, the frequency of unstable-type CAs (dicentrics and fragments) was not differ between these experimental groups (TBI+CRIPS vs. TBI). CRIPS does not seem to have a significant impact on initiation of radiocarcinogenesis of splenocytes because clastogenic effect of TBI was not enhanced by CRIPS. Further investigations elucidating possible modification effects from CRIPS on promotion and/or progression of radiocarcinogenesis of Trp53wt mice must be needed.
2015 RRS (Radiation Research Society)

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