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Klein PM, Alaghband Y, Doan NL, Ru N, Drayson OGG, Baulch JE, Kramár EA, Wood MA, Soltesz I, Limoli CL. Acute, Low-Dose Neutron Exposures Adversely Impact Central Nervous System Function. Int J Mol Sci 2021; 22:9020. [PMID: 34445726 PMCID: PMC8396607 DOI: 10.3390/ijms22169020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 02/06/2023] Open
Abstract
A recognized risk of long-duration space travel arises from the elevated exposure astronauts face from galactic cosmic radiation (GCR), which is composed of a diverse array of energetic particles. There is now abundant evidence that exposures to many different charged particle GCR components within acute time frames are sufficient to induce central nervous system deficits that span from the molecular to the whole animal behavioral scale. Enhanced spacecraft shielding can lessen exposures to charged particle GCR components, but may conversely elevate neutron radiation levels. We previously observed that space-relevant neutron radiation doses, chronically delivered at dose-rates expected during planned human exploratory missions, can disrupt hippocampal neuronal excitability, perturb network long-term potentiation and negatively impact cognitive behavior. We have now determined that acute exposures to similar low doses (18 cGy) of neutron radiation can also lead to suppressed hippocampal synaptic signaling, as well as decreased learning and memory performance in male mice. Our results demonstrate that similar nervous system hazards arise from neutron irradiation regardless of the exposure time course. While not always in an identical manner, neutron irradiation disrupts many of the same central nervous system elements as acute charged particle GCR exposures. The risks arising from neutron irradiation are therefore important to consider when determining the overall hazards astronauts will face from the space radiation environment.
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Affiliation(s)
- Peter M. Klein
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; (P.M.K.); (I.S.)
| | - Yasaman Alaghband
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Ngoc-Lien Doan
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Ning Ru
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Olivia G. G. Drayson
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Janet E. Baulch
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
| | - Enikö A. Kramár
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA; (E.A.K.); (M.A.W.)
| | - Marcelo A. Wood
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA; (E.A.K.); (M.A.W.)
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA; (P.M.K.); (I.S.)
| | - Charles L. Limoli
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (Y.A.); (N.-L.D.); (N.R.); (O.G.G.D.); (J.E.B.)
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Wang B, Yasuda H. Relative Biological Effectiveness of High LET Particles on the Reproductive System and Fetal Development. Life (Basel) 2020; 10:E298. [PMID: 33233778 PMCID: PMC7699951 DOI: 10.3390/life10110298] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/14/2020] [Accepted: 11/18/2020] [Indexed: 12/25/2022] Open
Abstract
During a space mission, astronauts are inevitably exposed to space radiation, mainly composed of the particles having high values of linear energy transfer (LET), such as protons, helium nuclei, and other heavier ions. Those high-LET particles could induce severer health damages than low-LET particles such as photons and electrons. While it is known that the biological effectiveness of a specified type of radiation depends on the distribution of dose in time, type of the cell, and the biological endpoint in respect, there are still large uncertainties regarding the effects of high-LET particles on the reproductive system, gamete, embryo, and fetal development because of the limitation of relevant data from epidemiological and experimental studies. To safely achieve the planned deep space missions to the moon and Mars that would involve young astronauts having reproductive functions, it is crucial to know exactly the relevant radiological effects, such as infertility of the parent and various diseases of the child, and then to conduct proper countermeasures. Thus, in this review, the authors present currently available information regarding the relative biological effectiveness (RBE) of high-LET particles on the deterministic effects related to the reproductive system and embryonic/fetal development for further discussions about the safety of being pregnant after or during a long-term interplanetary mission.
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Affiliation(s)
- Bing Wang
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan;
| | - Hiroshi Yasuda
- Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan
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3
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Guo J, Liu T, Ma L, Hao W, Yan H, Li T, Yang Y, Cai J, Gao F, Xu Z, Liu H. Polydatin Attenuates 14.1 MeV Neutron-Induced Injuries via Regulating the Apoptosis and Antioxidative Pathways and Improving the Hematopoiesis of Mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:8905860. [PMID: 32934763 PMCID: PMC7479486 DOI: 10.1155/2020/8905860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/01/2020] [Indexed: 11/17/2022]
Abstract
With more powerful penetrability and ionizing capability, high energetic neutron radiation (HENR) often poses greater threats than photon radiation, especially on such occasions as nuclear bomb exposure, nuclear accidents, aerospace conduction, and neutron-based radiotherapy. Therefore, there emerges an urgent unmet demand in exploring highly efficient radioprotectants against HENR. In the present study, high-throughput 14.1 MeV neutrons were generated by the high-intensity D-T fusion neutron generator (HINEG) and succeeded in establishing the acute radiation syndrome (ARS) mouse model induced by HENR. A series of preclinical studies, including morphopathological assessment, flow cytometry, peripheral complete blood, and bone marrow karyocyte counting, were applied showing much more serious detriments of HENR than the photon radiation. In specific, it was indicated that surviving fraction of polydatin- (PD-) treated mice could appreciably increase to up to 100% when they were exposed to HENR. Moreover, polydatin contributed much in alleviating the HENR-induced mouse body weight loss, spleen and testis indexes decrease, and the microstructure alterations of both the spleen and the bone marrow. Furthermore, we found that the HENR-damaged hematopoiesis was greatly prevented by PD treatment in such aspects as bone marrow hemocytogenesis, splenocytes balancing, or even the peripheral blood cellularity. The additional IHC investigations revealed that PD could exert potent hematopoiesis-promoting effects against HENR via suppressing apoptosis and promoting the antioxidative enzymes such as HO-1.
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Affiliation(s)
- Jiaming Guo
- Department of Radiation Medicine, College of Naval Medicine, Naval Medical University, Shanghai 200433, China
| | - Tingting Liu
- Department of Radiation Medicine, College of Naval Medicine, Naval Medical University, Shanghai 200433, China
| | - Long Ma
- Department of Reproductive Medicine Center, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Wei Hao
- Department of Endocrinology, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Hongli Yan
- Department of Reproductive Medicine Center, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Taosheng Li
- Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Yanyong Yang
- Department of Radiation Medicine, College of Naval Medicine, Naval Medical University, Shanghai 200433, China
| | - Jianming Cai
- Department of Radiation Medicine, College of Naval Medicine, Naval Medical University, Shanghai 200433, China
| | - Fu Gao
- Department of Radiation Medicine, College of Naval Medicine, Naval Medical University, Shanghai 200433, China
| | - Zhao Xu
- Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Hu Liu
- Department of Radiation Medicine, College of Naval Medicine, Naval Medical University, Shanghai 200433, China
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4
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Yang B, Ren BX, Tang FR. Prenatal irradiation-induced brain neuropathology and cognitive impairment. Brain Dev 2017; 39:10-22. [PMID: 27527732 DOI: 10.1016/j.braindev.2016.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 07/26/2016] [Accepted: 07/28/2016] [Indexed: 02/06/2023]
Abstract
Embryo/fetus is much more radiosensitive than neonatal and adult human being. The main potential effects of pre-natal radiation exposure on the human brain include growth retardation, small head/brain size, mental retardation, neocortical ectopias, callosal agenesis and brain tumor which may result in a lifetime poor quality of life. The patterns of prenatal radiation-induced effects are dependent not only on the stages of fetal development, the sensitivity of tissues and organs, but also on radiation sources, doses, dose rates. With the increased use of low dose radiation for diagnostic or radiotherapeutic purposes in recent years, combined with postnatal negative health effect after prenatal radiation exposure to fallout of Chernobyl nuclear power plant accident, the great anxiety and unnecessary termination of pregnancies after the nuclear disaster, there is a growing concern about the health effect of radiological examinations or therapies in pregnant women. In this paper, we reviewed current research progresses on pre-natal ionizing irradiation-induced abnormal brain structure changes. Subsequent postnatal neuropsychological and neurological diseases were provided. Relationship between irradiation and brain aging was briefly mentioned. The relevant molecular mechanisms were also discussed. Future research directions were proposed at the end of this paper. With limited human data available, we hoped that systematical review of animal data could relight research interests on prenatal low dose/dose rate irradiation-induced brain microanatomical changes and subsequent neurological and neuropsychological disorders.
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Affiliation(s)
- Bo Yang
- Medical School of Yangtze University, People's Republic of China
| | - Bo Xu Ren
- Medical School of Yangtze University, People's Republic of China.
| | - Feng Ru Tang
- Radiobiology Research Laboratory, Singapore Nuclear Research and Safety Initiative (SNRSI), National University of Singapore, Singapore.
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Katsura M, Cyou-Nakamine H, Zen Q, Zen Y, Nansai H, Amagasa S, Kanki Y, Inoue T, Kaneki K, Taguchi A, Kobayashi M, Kaji T, Kodama T, Miyagawa K, Wada Y, Akimitsu N, Sone H. Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells. Sci Rep 2016; 6:20027. [PMID: 26795421 PMCID: PMC4726121 DOI: 10.1038/srep20027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 10/19/2015] [Indexed: 12/24/2022] Open
Abstract
The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.
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Affiliation(s)
- Mari Katsura
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
| | - Hiromasa Cyou-Nakamine
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
- Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan
- Faculty of Pharmaceutical Sciences, Department of Pharmacy, Tokyo University of Science, Noda, Japan
| | - Qin Zen
- Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan
| | - Yang Zen
- Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan
| | - Hiroko Nansai
- Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan
| | - Shota Amagasa
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
| | - Yasuharu Kanki
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
| | - Tsuyoshi Inoue
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kiyomi Kaneki
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Akashi Taguchi
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Mika Kobayashi
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Toshiyuki Kaji
- Faculty of Pharmaceutical Sciences, Department of Pharmacy, Tokyo University of Science, Noda, Japan
| | - Tatsuhiko Kodama
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Kiyoshi Miyagawa
- Laboratory of Molecular Radiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Japan
| | - Youichiro Wada
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | | | - Hideko Sone
- Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan
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Yang M, Kim JS, Son Y, Kim J, Kim JY, Kim SH, Kim JC, Shin T, Moon C. Detrimental effect of fast neutrons on cultured immature rat hippocampal cells: relative biological effectiveness of in vitro cell death indices. Radiat Res 2011; 176:303-10. [PMID: 21692651 DOI: 10.1667/rr2589.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This in vitro study compared the detrimental effect and relative biological effectiveness (RBE) of high-linear energy transfer (LET) fast neutrons on rat immature hippocampal cultured cells with those of low-LET γ rays. Immature hippocampal cells were exposed to fast neutrons or γ rays. Cytotoxicity and cell viability were analyzed using a lactate dehydrogenase (LDH)-release assay and a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, respectively. The cytotoxicity and cell viability with fast neutrons or γ rays varied in a dose-dependent pattern. In the LDH release and MTT assay indices, the RBEs of fast neutrons were approximately 2.35 and 2.42, respectively. Fast neutrons markedly induced apoptotic changes in immature hippocampal cells with increased expression of active caspase-3 and cleaved poly(ADP-ribose) polymerase. Increased cytotoxicity and decreased cell viability in immature hippocampal cells were seen in a dose-dependent pattern after fast-neutron and γ irradiation. Fast neutrons have a higher RBE for cell death indices than γ rays.
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Affiliation(s)
- M Yang
- Department of Veterinary Anatomy, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, South Korea
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7
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Ishida Y, Ohmachi Y, Takai N, Hiraoka T, Ogiu T, Nishikawa T, Nishimura Y, Shimada Y. Neurobehavioral changes in mice exposed to fast neutrons in utero. JOURNAL OF RADIATION RESEARCH 2011; 52:257-263. [PMID: 21422737 DOI: 10.1269/jrr.10079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Epidemiological studies have revealed that radiation causes brain development abnormalities in atomic bomb survivors exposed in utero. Rat and mouse studies have also shown that prenatal exposure to low-linear energy transfer radiation induces developmental brain anomalies. Because the effects of prenatal irradiation on adult behavior patterns remain largely unknown, the present study investigated the effects of neutron exposure in utero on postnatal behavior patterns in mice. [C57BL/6J × C3H/He] hybrid (B6C3F1) mice were exposed to cyclotron-derived fast neutrons with peak energy of 10 MeV (0.02-0.2 Gy) or Cs-137 gamma-rays (0.2-1.5 Gy) on embryonic day 13.5. At 5.5-8 months of age, the neurobehavior of male offspring was examined by Rota-rod treadmill and locomotor activity. The accumulation of radio-labeled drug at muscarinic acetylcholine and serotonin receptors in mice from control and neutron-irradiated groups was determined by the tracer method. Locomotor activity during the dark period increased in the 0.02 Gy neutron-irradiated group. Furthermore, at 5.5 months of age, tracer binding in vivo to the muscarinic acetylcholine increased and to the serotonin receptors decreased in the 0.02 Gy neutron-irradiated group. In conclusion, the present study reveals that a certain "low-dose window" may exist for radiation-induced changes in neurobehavior and binding to neurotransmitter receptors, because there was correlation in neurobehavior and binding to neurotransmitter receptors in the 0.02 Gy neutron-irradiated group though there was not correlation in the neutron-irradiated groups more than 0.05 Gy.
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Affiliation(s)
- Yuka Ishida
- Department of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences, Chiba.
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8
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Yang M, Kim JS, Song MS, Kim JC, Shin T, Lee SS, Kim SH, Moon C. Dose-response and relative biological effectiveness of fast neutrons: induction of apoptosis and inhibition of neurogenesis in the hippocampus of adult mice. Int J Radiat Biol 2010; 86:476-85. [PMID: 20470197 DOI: 10.3109/09553001003667990] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE Our study compared the effects of high linear energy transfer (LET) fast neutrons on the induction of apoptosis and reduction of neurogenesis in the hippocampus of adult ICR mice with those of low-LET (60)Co gamma-rays, to evaluate the relative biological effectiveness (RBE) of fast neutrons in the adult hippocampal dentate gyrus (DG). MATERIALS AND METHODS The mice were exposed to 35 MeV fast neutrons or (60)Co gamma-rays. We evaluated acutely the incidence of apoptosis and expression of Ki-67 (a protein marker for cell proliferation originally defined by the monoclonal antibody Kiel-67) and doublecortin (DCX: an immature progenitor neuron marker) in the hippocampus after a single whole-body irradiation. RESULTS The number of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labelling (TUNEL)-positive apoptotic nuclei in the DG increased and both Ki-67- and DCX-positive cells declined in a dose-dependent pattern, with fast neutrons or gamma-rays. In the hippocampus, which showed an apoptosis frequency between 2 and 8 per DG, the RBE of fast neutrons was approximately 1.9. Additionally, the inhibitory effects of fast neutrons on the expression frequencies of Ki-67 (4-8) and DCX (8-32) were approximately 3.2 and 2.5 times, respectively, the effects of gamma-rays at the same dose. CONCLUSIONS Increased apoptotic cell death and decreased neurogenesis in the hippocampal DG were seen in a dose-dependent pattern after exposure to fast neutrons and gamma-rays. In addition, the different rate of hippocampal neurogenesis between different radiation qualities may be an index of RBE.
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Affiliation(s)
- Miyoung Yang
- Department of Veterinary Anatomy, College of Veterinary Medicine, Chonnam National University, Buk-Gu, Gwangju, South Korea
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Suda M, Hagihara T, Suya N, Hamano T, Takada M, Konishi T, Maeda T, Ohmachi Y, Kakinuma S, Ariyoshi K, Shimada Y, Imaseki H. Specifications of a neutron exposure accelerator system for biological effects experiments (NASBEE) in NIRS. Radiat Phys Chem Oxf Engl 1993 2009. [DOI: 10.1016/j.radphyschem.2009.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Kuhne WW, Gersey BB, Wilkins R, Wu H, Wender SA, George V, Dynan WS. Biological effects of high-energy neutrons measured in vivo using a vertebrate model. Radiat Res 2009; 172:473-80. [PMID: 19772468 DOI: 10.1667/rr1556.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Interaction of solar protons and galactic cosmic radiation with the atmosphere and other materials produces high-energy secondary neutrons from below 1 to 1000 MeV and higher. Although secondary neutrons may provide an appreciable component of the radiation dose equivalent received by space and high-altitude air travelers, the biological effects remain poorly defined, particularly in vivo in intact organisms. Here we describe the acute response of Japanese medaka (Oryzias latipes) embryos to a beam of high-energy spallation neutrons that mimics the energy spectrum of secondary neutrons encountered aboard spacecraft and high-altitude aircraft. To determine RBE, embryos were exposed to 0-0.5 Gy of high-energy neutron radiation or 0-15 Gy of reference gamma radiation. The radiation response was measured by imaging apoptotic cells in situ in defined volumes of the embryo, an assay that provides a quantifiable, linear dose response. The slope of the dose response in the developing head, relative to reference gamma radiation, indicates an RBE of 24.9 (95% CI 13.6-40.7). A higher RBE of 48.1 (95% CI 30.0-66.4) was obtained based on overall survival. A separate analysis of apoptosis in muscle showed an overall nonlinear response, with the greatest effects at doses of less than 0.3 Gy. Results of this experiment indicate that medaka are a useful model for investigating biological damage associated with high-energy neutron exposure.
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Affiliation(s)
- Wendy W Kuhne
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA.
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Zhang Y, Li S, Liang Y, Wen C, Guo Q, Su B. Potential mechanisms of neuroprotection induced by low dose total-body γ-irradiation in C57 mice administered with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Neurosci Lett 2009; 450:106-10. [DOI: 10.1016/j.neulet.2008.11.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 11/02/2008] [Accepted: 11/16/2008] [Indexed: 10/21/2022]
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12
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Satoh D, Takahashi F, Endo A, Ohmachi Y, Miyahara N. Calculation of dose contributions of electron and charged heavy particles inside phantoms irradiated by monoenergetic neutron. JOURNAL OF RADIATION RESEARCH 2008; 49:503-508. [PMID: 18580044 DOI: 10.1269/jrr.08009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The radiation-transport code PHITS with an event generator mode has been applied to analyze energy depositions of electrons and charged heavy particles in two spherical phantoms and a voxel-based mouse phantom upon neutron irradiation. The calculations using the spherical phantoms quantitatively clarified the type and energy of charged particles which are released through interactions of neutrons with the phantom elements and contribute to the radiation dose. The relative contribution of electrons increased with an increase in the size of the phantom and with a decrease in the energy of the incident neutrons. Calculations with the voxel-based mouse phantom for 2.0-MeV neutron irradiation revealed that the doses to different locations inside the body are uniform, and that the energy is mainly deposited by recoil protons. The present study has demonstrated that analysis using PHITS can yield dose distributions that are accurate enough for RBE evaluation.
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Affiliation(s)
- Daiki Satoh
- Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, Japan.
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13
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Yasuda T, Yoshimoto M, Maeda K, Matsumoto A, Maruyama K, Ishikawa Y. Rapid and simple method for quantitative evaluation of neurocytotoxic effects of radiation on developing medaka brain. JOURNAL OF RADIATION RESEARCH 2008; 49:533-540. [PMID: 18654045 DOI: 10.1269/jrr.08030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We describe a novel method for rapid and quantitative evaluation of the degree of radiation-induced apoptosis in the developing brain of medaka (Oryzias latipes). Embryos at stage 28 were irradiated with 1, 2, 3.5, and 5 Gy x-ray. Living embryos were stained with a vital dye, acridine orange (AO), for 1-2 h, and whole-mount brains were examined under an epifluorescence microscope. From 7 to 10 h after irradiation with 5 Gy x-ray, we found two morphologically different types of AO-stained structures, namely, small single nuclei and rosette-shaped nuclear clusters. Electron microscopy revealed that these two distinct types of structures were single apoptotic cells with condensed nuclei and aggregates of apoptotic cells, respectively. From 10 to 30 h after irradiation, a similar AO-staining pattern was observed. The numbers of AO-stained rosette-shaped nuclear clusters and AO-stained single nuclei increased in a dose-dependent manner in the optic tectum. We used the number of AO-stained rosette-shaped nuclear clusters/optic tectum as an index of the degree of radiation-induced brain cell death at 20-24 h after irradiation. The results showed that the number of rosette-shaped nuclear clusters/optic tectum in irradiated embryos exposed to 2 Gy or higher doses was highly significant compared to the number in nonirradiated control embryos, whereas no difference was detected at 1 Gy. Thus, the threshold dose for brain cell death in medaka embryos was taken as being between 1-2 Gy, which may not be so extraordinarily large compared to those for rodents and humans. The results show that medaka embryos are useful for quantitative evaluation of developmental neurocytotoxic effects of radiation.
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Affiliation(s)
- Takako Yasuda
- Environmental Radiation Effects Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan.
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14
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Ionizing radiation downregulates ASPM, a gene responsible for microcephaly in humans. Biochem Biophys Res Commun 2008; 369:953-7. [DOI: 10.1016/j.bbrc.2008.02.149] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 02/27/2008] [Indexed: 11/16/2022]
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15
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Lee HJ, Kim JS, Moon C, Kim JC, Jo SK, Kim SH. Relative biological effectiveness of fast neutrons in a multiorgan assay for apoptosis in mouse. ENVIRONMENTAL TOXICOLOGY 2008; 23:233-239. [PMID: 18214905 DOI: 10.1002/tox.20328] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This study compared the effects of high linear energy transfer (LET) fast neutrons on the induction of apoptosis in several tissue types (hair follicle, intestine crypt, testis) of ICR mouse exposed to low LET 60Co gamma-rays. The changes that occurred from 0 to 24 h after exposing the mice to either 2 Gy of gamma-rays (2 Gy/min) or 0.8 Gy of neutrons (94 mGy/min, 35 MeV) were examined. The maximum frequency of apoptosis was observed at 8 or 12 h after irradiation. The mice that had received 0-8 Gy of gamma-rays or 0-1.6 Gy of neutrons were examined 8 h after irradiation. The best-fitting dose-response curves were linear-quadratic, and there was a significant relationship between the number of apoptotic cells and the dose. The stained products in the TUNEL-positive cells or bodies correlated with the typical morphologic characteristics of apoptosis observed by optical microscopy. In the follicles showing an apoptosis frequency between 2 and 14 per hair follicle, the relative biological effectiveness (RBE) of the neutrons in the small and large follicles was 2.09 +/- 0.31 and 2.15 +/- 0.18, respectively. In the intestine crypts showing an apoptosis frequency between 1 and 3 per crypt, the RBE of the neutrons was 4.03 +/- 0.06 and 3.87 +/- 0.04 in the base and total crypts, respectively. The RBE of the neutrons in the seminiferous tubule showing an apoptosis frequency between 0.5 and 2 per tubule was 5.18 +/- 0.06. The results determined the time-response relations and the RBE for fast neutron-induced apoptosis in several organs at the same time. The differences in RBE observed between the high and low LET radiation and it is believed that the difference in the DSB repair capacity in hair follicle, intestine crypt, and seminiferous tubule cells plays a role in determining the RBE of the high-LET radiation for the induced apoptotic cell formation.
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Affiliation(s)
- Hae-June Lee
- Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Science, Seoul 139-240, South Korea
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Lee HJ, Kim SH. Relative biological effectiveness of fast neutrons for apoptosis in mouse hair follicles. J Vet Sci 2007; 8:335-40. [PMID: 17993746 PMCID: PMC2868148 DOI: 10.4142/jvs.2007.8.4.335] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study compared the effects of high linear energy transfer (LET) fast neutrons on the induction of apoptosis in the hair follicles of ICR mice with those of low LET 60Co γ-rays. The changes that occurred from 0 to 24 h after exposing the mice to either 2 Gy of γ-rays (2 Gy/min) or 0.8 Gy of neutrons (94 mGy/min, 35 MeV) were examined. The maximum frequency was found at 12 h (γ-rays) or 8 h (neutrons) after irradiation. The mice that received 0-8 Gy of γ-rays or 0-1.6 Gy of neutrons were examined 8 h after irradiation. The dose-response curves were analyzed using the best-fit curve model. The dose-response curves were linear-quadratic, and a significant relationship was found between the frequency of apoptotic cells and the dose. The morphological findings in the irradiated groups were typical apoptotic fragments in the matrix region of the hair follicle, but the spontaneous existence of apoptotic fragments was rarely observed in the control group. In the presence of an apoptosis frequency between 2 and 14 per follicle, the relative biological effectiveness values of neutrons in small and large follicles were 2.09 ± 0.30 and 2.15 ± 0.18, respectively.
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Affiliation(s)
- Hae-June Lee
- Korea Institute of Radiological & Medical Science, Seoul 139-240, Korea
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Jeong WI, DO SH, Kim TH, Jeong DH, Hong IH, Ki MR, Kwak DM, Lee SS, Jee YH, Kim SB, Jeong KS. Acute effects of fast neutron irradiation on mouse liver. JOURNAL OF RADIATION RESEARCH 2007; 48:233-40. [PMID: 17536182 DOI: 10.1269/jrr.0629] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Until now, the multiple biological effects of ionizing radiation on liver have been reported. However, there has not been any reports of fast neutron-mediated liver injuries including liver regeneration or fibrosis. Here, we described the biological effects of acute fast neutron irradiation on the liver. After the fast neutron irradiation of 0, 0.25, 1, 2, 4 and 8 Gy on mice, hepatocyte necrosis and a decrease in the total number of hepatocytes were induced dose-dependently. Binucleated hepatocytes and PCNA positive hepatocytes increased significantly at 0.25 and 1 Gy, but decreased markedly at 2, 4 and 8 Gy. The expression of cytochrome P450 2E1 (CYP2E1) showed a dose-dependent increase after fast neutron irradiation. The activation of p-Smad2/3, signaling intermediates of transforming growth factor-beta (TGF-beta), increased in hepatocytes after exposure of 0.25, 1, and 2 Gy of fast neutrons, but it was not detected in hepatic stellate cells (HSCs). In conclusion, fast neutron-induced liver damages, likely loss of hepatocytes, necrotic foci and vacuolar changes, were note on the dose dependent manner and hepatocellular regeneration were significantly diminished at doses of 2, 4 and 8Gy in a dose-dependent manner. These alterations may at least in part be associated with dose-dependent increase in CYP2E1 and p-Smad2/3. These results show promise as an approach for the treatment of fast neutrons on liver tumors and in the study of pathogenesis regarding the fast neutron-irradiated damages of the liver.
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Affiliation(s)
- Won-Il Jeong
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea
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