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Gridley DS, Pecaut MJ. Changes in the distribution and function of leukocytes after whole-body iron ion irradiation. JOURNAL OF RADIATION RESEARCH 2016; 57:477-491. [PMID: 27380804 PMCID: PMC5045078 DOI: 10.1093/jrr/rrw051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/11/2016] [Accepted: 04/03/2016] [Indexed: 06/06/2023]
Abstract
High-energy particle radiation could have a considerable impact on health during space missions. This study evaluated C57BL/6 mice on Day 40 after total-body 56Fe26+ irradiation at 0, 1, 2 and 3 gray (Gy). Radiation consistently increased thymus mass (one-way ANOVA: P < 0.005); spleen, liver and lung masses were similar among all groups. In the blood, there was no radiation effect on the white blood cell (WBC) count or major leukocyte types. However, the red blood cell count, hemoglobin, hematocrit and the CD8+ T cytotoxic (Tc) cell count and percentage all decreased, while both the CD4:CD8 (Th:Tc) cell ratio and spontaneous blastogenesis increased, in one or more irradiated groups compared with unirradiated controls (P < 0.05 vs 0 Gy). In contrast, splenic WBC, lymphocyte, B cell and T helper (Th) counts, %B cells and the CD4:CD8 ratio were all significantly elevated, while Tc percentages decreased, in one or more of the irradiated groups compared with controls (P < 0.05 vs 0 Gy). Although there were trends for minor, radiation-induced increases in %CD11b+ granulocytes in the spleen, cells double-labeled with adhesion markers (CD11b+CD54+, CD11b+CD62E+) were normal. Splenocyte spontaneous blastogenesis and that induced by mitogens (PHA, ConA, LPS) was equivalent to normal. In bone marrow, the percentage of cells expressing stem cell markers, Sca-1 and CD34/Sca-1, were low in one or more of the irradiated groups (P < 0.05 vs 0 Gy). Collectively, the data indicate that significant immunological abnormalities still exist more than a month after 56Fe irradiation and that there are differences dependent upon body compartment.
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Affiliation(s)
- Daila S Gridley
- Department of Basic Sciences, Division of Radiation Research, Loma Linda University School of Medicine, Chan Shun Pavilion, 11175 Campus Street, Loma Linda, CA 92354, USA
| | - Michael J Pecaut
- Department of Basic Sciences, Division of Radiation Research, Loma Linda University School of Medicine, Chan Shun Pavilion, 11175 Campus Street, Loma Linda, CA 92354, USA
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Chang PY, Cucinotta FA, Bjornstad KA, Bakke J, Rosen CJ, Du N, Fairchild DG, Cacao E, Blakely EA. Harderian Gland Tumorigenesis: Low-Dose and LET Response. Radiat Res 2016; 185:449-60. [PMID: 27092765 DOI: 10.1667/rr14335.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Increased cancer risk remains a primary concern for travel into deep space and may preclude manned missions to Mars due to large uncertainties that currently exist in estimating cancer risk from the spectrum of radiations found in space with the very limited available human epidemiological radiation-induced cancer data. Existing data on human risk of cancer from X-ray and gamma-ray exposure must be scaled to the many types and fluences of radiations found in space using radiation quality factors and dose-rate modification factors, and assuming linearity of response since the shapes of the dose responses at low doses below 100 mSv are unknown. The goal of this work was to reduce uncertainties in the relative biological effect (RBE) and linear energy transfer (LET) relationship for space-relevant doses of charged-particle radiation-induced carcinogenesis. The historical data from the studies of Fry et al. and Alpen et al. for Harderian gland (HG) tumors in the female CB6F1 strain of mouse represent the most complete set of experimental observations, including dose dependence, available on a specific radiation-induced tumor in an experimental animal using heavy ion beams that are found in the cosmic radiation spectrum. However, these data lack complete information on low-dose responses below 0.1 Gy, and for chronic low-dose-rate exposures, and there are gaps in the LET region between 25 and 190 keV/μm. In this study, we used the historical HG tumorigenesis data as reference, and obtained HG tumor data for 260 MeV/u silicon (LET ∼70 keV/μm) and 1,000 MeV/u titanium (LET ∼100 keV/μm) to fill existing gaps of data in this LET range to improve our understanding of the dose-response curve at low doses, to test for deviations from linearity and to provide RBE estimates. Animals were also exposed to five daily fractions of 0.026 or 0.052 Gy of 1,000 MeV/u titanium ions to simulate chronic exposure, and HG tumorigenesis from this fractionated study were compared to the results from single 0.13 or 0.26 Gy acute titanium exposures. Theoretical modeling of the data show that a nontargeted effect model provides a better fit than the targeted effect model, providing important information at space-relevant doses of heavy ions.
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Affiliation(s)
- Polly Y Chang
- a Biosciences Division, SRI International, Menlo Park, California 94025;,b Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; and
| | - Francis A Cucinotta
- c Department of Health Physics and Diagnostic Sciences, University of Nevada, Las Vegas, Nevada 89154
| | - Kathleen A Bjornstad
- b Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; and
| | - James Bakke
- a Biosciences Division, SRI International, Menlo Park, California 94025
| | - Chris J Rosen
- a Biosciences Division, SRI International, Menlo Park, California 94025
| | - Nicholas Du
- b Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; and
| | - David G Fairchild
- b Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; and
| | - Eliedonna Cacao
- c Department of Health Physics and Diagnostic Sciences, University of Nevada, Las Vegas, Nevada 89154
| | - Eleanor A Blakely
- b Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; and
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Radiation-induced changes in DNA methylation of repetitive elements in the mouse heart. Mutat Res 2016; 787:43-53. [PMID: 26963372 DOI: 10.1016/j.mrfmmm.2016.02.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 02/02/2016] [Accepted: 02/28/2016] [Indexed: 01/04/2023]
Abstract
DNA methylation is a key epigenetic mechanism, needed for proper control over the expression of genetic information and silencing of repetitive elements. Exposure to ionizing radiation, aside from its strong genotoxic potential, may also affect the methylation of DNA, within the repetitive elements, in particular. In this study, we exposed C57BL/6J male mice to low absorbed mean doses of two types of space radiation-proton (0.1 Gy, 150 MeV, dose rate 0.53 ± 0.08 Gy/min), and heavy iron ions ((56)Fe) (0.5 Gy, 600 MeV/n, dose rate 0.38 ± 0.06 Gy/min). Radiation-induced changes in cardiac DNA methylation associated with repetitive elements were detected. Specifically, modest hypomethylation of retrotransposon LINE-1 was observed at day 7 after irradiation with either protons or (56)Fe. This was followed by LINE-1, and other retrotransposons, ERV2 and SINE B1, as well as major satellite DNA hypermethylation at day 90 after irradiation with (56)Fe. These changes in DNA methylation were accompanied by alterations in the expression of DNA methylation machinery and affected the one-carbon metabolism pathway. Furthermore, loss of transposable elements expression was detected in the cardiac tissue at the 90-day time-point, paralleled by substantial accumulation of mRNA transcripts, associated with major satellites. Given that the one-carbon metabolism pathway can be modulated by dietary modifications, these findings suggest a potential strategy for the mitigation and, possibly, prevention of the negative effects exerted by ionizing radiation on the cardiovascular system. Additionally, we show that the methylation status and expression of repetitive elements may serve as early biomarkers of exposure to space radiation.
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Kase KR. Twelfth Annual Warren K. Sinclair Keynote Address--the Influence of the NCRP on Radiation Protection in the United States: Guidance and Regulation. HEALTH PHYSICS 2016; 110:127-145. [PMID: 26717165 DOI: 10.1097/hp.0000000000000408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The Warren K. Sinclair Keynote Address for the 2015 Annual Meeting of the National Council on Radiation Protection and Measurements (NCRP) describes the Council's influence in the development of radiation protection guidance in the United States since its founding in 1929 as the U.S. Advisory Committee on X-Ray and Radium Protection. The National Bureau of Standards (NBS) was the coordinating agency for the Advisory Committee, and its reports were published as NBS handbooks. In 1946, the Advisory Committee was renamed the National Committee on Radiation Protection and remained so until NCRP was chartered by the U.S. Congress in 1964. In 1931, the U.S. Advisory Committee on X-Ray and Radium Protection proposed the first formal standard for protecting people from radiation sources as NBS Handbook 15 and issued the first handbook on radium protection, NBS Handbook 18. Revised recommendations for external exposure were issued in 1936 and for radium protection in 1938 and remained in force until 1948. Throughout its 86 y history, the Council and its predecessors have functioned as effective advisors to the nation on radiation protection issues and have provided the fundamental guidance and recommendations necessary for the regulatory basis of the control of radiation exposure, radiation-producing devices, and radioactive materials in the United States.
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Indo HP, Tomiyoshi T, Suenaga S, Tomita K, Suzuki H, Masuda D, Terada M, Ishioka N, Gusev O, Cornette R, Okuda T, Mukai C, Majima HJ. MnSOD downregulation induced by extremely low 0.1 mGy single and fractionated X-rays and microgravity treatment in human neuroblastoma cell line, NB-1. J Clin Biochem Nutr 2015; 57:98-104. [PMID: 26388666 PMCID: PMC4566025 DOI: 10.3164/jcbn.15-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 02/16/2015] [Indexed: 11/22/2022] Open
Abstract
A human neuroblastoma cell line, NB-1, was treated with 24 h of microgravity simulation by clinostat, or irradiated with extremely small X-ray doses of 0.1 or 1.0 mGy using single and 10 times fractionation regimes with 1 and 2 h time-intervals. A quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) examination was performed for apoptosis related factors (BAX, CYTC, APAF1, VDAC1–3, CASP3, CASP8, CASP9 P53, AIF, ANT1 and 2, BCL2, MnSOD, autophagy related BECN and necrosis related CYP-40. The qRT-PCR results revealed that microgravity did not result in significant changes except for a upregulation of proapoptotic VDAC2, and downregulations of proapoptotic CASP9 and antiapoptotic MnSOD. After 0.1 mGy fractionation irradiation, there was increased expression of proapoptotic APAF1 and downregulation of proapoptotic CYTC, VDAC2, VDAC3, CASP8, AIF, ANT1, and ANT2, as well as an increase in expression of antiapoptotic BCL2. There was also a decrease in MnSOD expression with 0.1 mGy fractionation irradiation. These results suggest that microgravity and low-dose radiation may decrease apoptosis but may potentially increase oxidative stress.
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Affiliation(s)
- Hiroko P Indo
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Tsukasa Tomiyoshi
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Shigeaki Suenaga
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Kazuo Tomita
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Hiromi Suzuki
- Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan ; Life Science Research Group, Department of Science and Applications, Japan Space Forum, 3-2-1 Surugadai, Chiyoda, Tokyo 100-0004, Japan
| | - Daisuke Masuda
- Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan ; Utilization & Engineering Department, Japan Manned Space Systems Corporation, 2-1-6 Tsukuba, Ibaraki 305-0047, Japan
| | - Masahiro Terada
- Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan ; Space Biosciences Division, NASA Ames Research Center, Moffett Field, California 94035, USA
| | - Noriaki Ishioka
- Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan ; Department of Space Biology and Microgravity Sciences, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505, Japan
| | - Oleg Gusev
- Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan ; Department of Space Biology and Microgravity Sciences, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505, Japan ; Department of Invertebrates Zoology and Functional Morphology, Institute of Fundamental Medicine and Biology, Kazan Federal University 420008, Kremevskaya str., 17 Kazan 420-008, Russia ; Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Richard Cornette
- Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Takashi Okuda
- Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Chiaki Mukai
- Center for Applied Space Medicine and Human Research, Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505, Japan
| | - Hideyuki J Majima
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan ; Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
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