Radiation response of apoptosis in C57BL/6N mouse spleen after whole-body irradiation

Takahashi, Akio; Ohnishi, Ken; Asakawa, Isao; Kondo, Natsuko; Nakagawa, Hiroyuki; Yonezawa, Morio; Tachibana, Akira; Matsumoto, Hideki; Ohnishi, Takeo

doi:10.1080/09553000110062873

Cited by 57 publications

(24 citation statements)

References 13 publications

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“…Recently, we reported that the radioadaptive response in mice seems to be induced through the reduction of Trp53-centered apoptosis in hematopoietic stem cells after high-dose exposure (37). Takahashi et al reported that apoptosis of the splenic white pulp (lymphoid organ enclosed by a columnar arterial branch) induced by X irradiation at 3 Gy was suppressed by a chronic low-dose-rate preirradiation (38). In our study, we speculate that the preirradiation could have induced radioresistance in hematopoietic stem cells 9-17 days after exposure, resulting in a swift recovery of the stem cell numbers without stimulated hematopoiesis, allowing in-166 YONEZAWA ET AL.…”

Section: Discussionmentioning

confidence: 99%

Increase in Endogenous Spleen Colonies without Recovery of Blood Cell Counts in Radioadaptive Survival Response in C57BL/6 Mice

et al. 2004

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The radioadaptive survival response induced by a conditioning exposure to 0.45 Gy and measured as an increase in 30-day survival after mid-lethal X irradiation was studied in C57BL/6N mice. The acquired radioresistance appeared on day 9 after the conditioning exposure, reached a maximum on days 12-14, and disappeared on day 21. The conditioning exposure 14 days prior to the challenge exposure increased the number of endogenous spleen colonies (CFU-S) on days 12-13 after the exposure to 5 Gy. On day 12 after irradiation, the conditioning exposure also increased the number of endogenous CFU-S to about five times that seen in animals exposed to 4.25-6.75 Gy without preirradiation. The effect of the interval between the preirradiation and the challenge irradiation on the increase in endogenous CFU-S was also examined. A significant increase in endogenous CFU-S was observed when the interval was 14 days, but not 9 days. This result corresponded to the increase in survival observed on day 14 after the challenge irradiation. Radiation-inducted resistance to radiation-induced lethality in mice appears to be closely related to the marked recovery of endogenous CFU-S in the surviving hematopoietic stem cells that acquired radioresistance by preirradiation. Preirradiation enhanced the recovery of the numbers of erythrocytes, leukocytes and thrombocytes very slightly in mice exposed to a sublethal dose of 5 Gy, a dose that does not cause bone marrow death. There appears to be no correlation between the marked increase in endogenous CFU-S and the slight increase or no increase in peripheral blood cells induced by the radioadaptive response. The possible contribution by some factor, such as Il4 or Il11, that has been reported to protect irradiated animals without stimulating hematopoiesis is discussed.

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Section: Discussionmentioning

confidence: 99%

Increase in Endogenous Spleen Colonies without Recovery of Blood Cell Counts in Radioadaptive Survival Response in C57BL/6 Mice

et al. 2004

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“…16). Our group has reported that p53-dependent apoptosis after exposure to high-dose radiation was also found to be suppressed by chronic irradiation in cultured cells in vitro and in the spleens of mice in vivo (17). In addition, it seems that p53 can control the secretion of certain growthinhibitory factors in response to stress in vitro and in vivo (18).…”

Section: Introductionmentioning

confidence: 98%

Nitric Oxide Radicals Choreograph a Radioadaptive Response

2007

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The reduced biological effects of radiation exposure seen in cells after conditioning exposures to a low dose or at a lowdose rate (i.e., the acquisition of resistance against high-dose radiation) is called the ''radioadaptive response'' and many studies concerning this phenomenon have been reported since the 1980s. Radioadaptive responses have been observed using various end points, such as chromosomal aberrations, mutations, and clonogenic survival. However, the mechanisms of the radioadaptive response are not fully known. Here, we show that radiation-induced nitric oxide (NO) radicals contribute to the induction of radioresistance as determined by cell survival after a subsequent high-dose exposure. An accumulation of inducible NO synthase was produced, and the concentration of nitrite in the culture medium increased when cells were exposed to ;-rays at a low-dose rate or to X-rays for a low dose followed by an acute high-dose X-irradiation. In addition, the induction of radioresistance was not observed in the presence of an inhibitor of inducible NO synthase or a scavenger of NO radicals. Moreover, radioresistance was observed when cultures were treated with a NO radicalgenerating agent. These findings suggest that NO radicals are an initiator of the radioadaptive response. [Cancer Res 2007;67(18):8574-9]

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“…Of particular interest in the adaptive response is the dose window (i.e., the specific range of doses and/or dose rates) that can serve as a priming irradiation or conditioning irradiation before a challenging irradiation (6)(7)(8). It has been reported that a priming or conditioning low-dose exposure, or an exposure with low dose rates, can induce a p53 tumor suppressor gene-dependent adaptive response in mammalian cells (9)(10)(11)(12)(13). This observation is of interest because the radiation environment in space includes low doses and low dose rates.…”

Section: Introductionmentioning

confidence: 99%

53-Dependent Adaptive Responses in Human Cells Exposed to Space Radiations

Takahashi

Suzuki

et al. 2010

International Journal of Radiation Oncology*Biology*Physics

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Radiation response of apoptosis in C57BL/6N mouse spleen after whole-body irradiation

Abstract: Chronic pre-irradiation at a low dose-rate suppressed Bax-mediated apoptosis. These findings suggest that the radioadaptive response in mouse spleen may be due to a suppression of p53-mediated apoptosis.

Cited by 57 publications

References 13 publications

Increase in Endogenous Spleen Colonies without Recovery of Blood Cell Counts in Radioadaptive Survival Response in C57BL/6 Mice

Increase in Endogenous Spleen Colonies without Recovery of Blood Cell Counts in Radioadaptive Survival Response in C57BL/6 Mice

Nitric Oxide Radicals Choreograph a Radioadaptive Response

53-Dependent Adaptive Responses in Human Cells Exposed to Space Radiations

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