Two types of X-ray-induced radioresistance in mice: Presence of 4 dose ranges with distinct biological effects

Immunological mechanism of low-dose priming radiation resistance in walker-256 tumor model mice

“…A previous study reported that, in mice treated with 0.05 Gy priming radiation, the frequency of radioresistance significantly increased and persisted for 2-2.5 months. However, radiation priming with 0.30 Gy and 0.50 Gy resulted in radioresistance 2 weeks later, but this radioresistance was no longer observed 2 months later (19). The results indicated that the biological effects of ionizing radiation may be distinguished with the different priming radiation dose, which may be further investigated in future studies.…”

X-Ray-Induced Radioresistance Against High-LET Radiations from Accelerated Neon-Ion Beams in Mice

“…The priming dose at 0.5 Gy adopted from Yonezawa et al's work (Yonezawa et al, 1996) and a challenging dose at 7.5 Gy which resulted in about 80% mortality in C57BL/6J Jms female mice when whole body exposed to X-rays at 8 weeks old, were delivered to the animals on postnatal ages of 6 and 8 weeks, respectively. Results (Fig.…”

“…One set of the conditions essential for AR induction in the mouse model established by Yonezawa et al (Yonezawa et al, 1996) was adopted, verified and confirmed under the experimental conditions in our research facilities, and finally applied to the present study. In brief, the efficient priming dose of X-rays was 0.5 Gy.…”

“…In a series of comprehensive studies, a variety of experimental condition combinations of the priming and challenging doses, the interval between the irradiations, and the mouse strain were testified and verified (Yonezawa, 2006), laying a cornerstone of in vivo model for AR in mice -successful establishment of the mouse models for AR induction by acute low liner energy transfer (LET) X-irradiations at the whole body level using survival from bone marrow death as the main endpoint, which is the so-called "Yonezawa Effect" in Japan (Takahashi & Ohnishi, 2009). The mouse models for AR induction (Yonezawa, 1996) were with great reliability and reproducibility in different laboratories (Nose et al, 2001;Otsuka et al, 2008;). The induced AR could be generally divided into two phenotypes according to the attitude of the priming dose and the interval between the priming and challenging irradiation, involving different mechanisms: AR induced 2 weeks after a priming irradiation at a dose from 0.3 to 0.5 Gy was due to radioresistance occurred in blood forming tissues which was a Trp53 dependent event (Otsuka et al, 2008;Horie et al, 2002), and interaction between blood forming tissue and the central nervous system was thought to contribute to AR induced 2 months after a priming dose at 0.05 or 0.1 Gy (Yonezawa, 2000;Misonoh & Yonezawa, 1997).…”

Radio-protective response on the environmental pollutant induced oxidative stress

“…Moreover, Azzam, suggested that a single low dose at background or occupational exposure level may reduce cancer risk [4], while Yonezawa and his colleagues indicated that pre-irradiated mice with 50 cGy of X rays increased the survival rats about 70% after subsequent lethal high dose irradiation [5]. According to Manno, Yamoaka, Kojima and their colleagues and Feinendegen, pre-irradiated animals with low dose may enhance the activities of SOD, GSH-Px [2,[6][7][8], while Nomura and Yomaoka, suggested that low dose radiation reduced oxidative damage induced by CCl 4 in mouse liver, this by increasing the endogenous antioxidant in animal tissues [9].…”