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Shichijo K, Takatsuji T, Uzbekov D, Chaizhunusova N, Shabdarbaeva D, Kurisu M, Takahashi Y, Stepanenko V, Azhimkhanov A, Hoshi M. Radiation makes cells select the form of death dependent on external or internal exposure: apoptosis or pyroptosis. Sci Rep 2023; 13:12002. [PMID: 37491560 PMCID: PMC10368746 DOI: 10.1038/s41598-023-38789-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 07/14/2023] [Indexed: 07/27/2023] Open
Abstract
Internal radiation exposure from neutron-induced radioisotopes environmentally activated following atomic bombing or nuclear accidents should be considered for a complete picture of pathologic effects on survivors. Acute and localized high dose radiation exposure from hot particles taken into the body must induce cell death and severe damage to tissues, whether they are proliferating or not. However, very little the cellular and molecular mechanisms underlying this internal radiation pathology has been investigated. Male Wistar rats were internally exposed to 56MnO2 powder by inhalation. Small intestine samples were investigated by histological staining at acute phase (6 h, 3 days and 14 days) and late phase (2, 6 and 8 months) after the exposure. Histological location and chemical properties of the hot particles embedded in small intestinal tissues were analyzed by synchrotron radiation-X-ray fluorescence-X-ray absorption near-edge structure (SR-XRF-XANES). Hot particles located in the intestinal cavity were identified as accumulations of Mn and iron. Pathological changes showed evidence of crypt shortening, massive cell death at the position of stem cell zone, including apoptosis and pyroptosis from 6 h through 8 months in the internal exposed rats.
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Affiliation(s)
- Kazuko Shichijo
- Department of Tumor and Diagnostic Pathology, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
| | - Toshihiro Takatsuji
- Nagasaki University, 1-14 Bunkyo, Nagasaki, 852-8521, Japan
- School of Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Shimotsugagun, Tochigi, 321-0293, Japan
| | - Darkhan Uzbekov
- Department of Pathological Anatomy and Forensic Medicine, Semey State Medical University, Abay Str., 103, Semey, 071400, Kazakhstan
| | - Nailya Chaizhunusova
- Department of Pathological Anatomy and Forensic Medicine, Semey State Medical University, Abay Str., 103, Semey, 071400, Kazakhstan
| | - Dariya Shabdarbaeva
- Department of Pathological Anatomy and Forensic Medicine, Semey State Medical University, Abay Str., 103, Semey, 071400, Kazakhstan
| | - Minako Kurisu
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsusima-cho, Yokosuka-shi, Kanagawa, 237-0061, Japan
| | - Yoshio Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Valeriy Stepanenko
- A.Tsyb Medical Radiological Research Center-National Medical Research Center of Radiology, Ministry of Health of Russian Federation, 249036, Obninsk, Russia
| | - Almas Azhimkhanov
- National Nuclear Center of the Republic of Kazakhstan, Beibyt atom st., 2B, Kurchatov, 071100, Kazakhstan
| | - Masaharu Hoshi
- The Center for Peace, Hiroshima University, Higashi-senda-machi, Naka-ku, Hiroshima, 730-0053, Japan
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Inoue K, Kawano N, Fujimoto N, Takeichi N, Hoshi M. The need for measures to prevent radiation exposure in Ukraine, taking both internal and external exposure into account. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2023; 266-267:107238. [PMID: 37413824 DOI: 10.1016/j.jenvrad.2023.107238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/08/2023]
Affiliation(s)
- Ken Inoue
- Research and Education Faculty, Medical Sciences Cluster, Health Service Center, Kochi University 2-5-1, Akebono-cho, Kochi-shi, Kochi, 780-8520, Japan; The Center for Peace, Hiroshima University 1-1-89, Higashisendamachi, Naka-ku, Hiroshima-shi, Hiroshima, 730-0053, Japan.
| | - Noriyuki Kawano
- The Center for Peace, Hiroshima University 1-1-89, Higashisendamachi, Naka-ku, Hiroshima-shi, Hiroshima, 730-0053, Japan.
| | - Nariaki Fujimoto
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima-shi, Hiroshima, 734-8553, Japan.
| | - Nobuo Takeichi
- Takeichi Clinic, 1-33, Nishikoujinmachi, Minami-ku, Hiroshima-shi, Hiroshima, 732-0806, Japan; Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima-shi, Hiroshima, 734-8553, Japan.
| | - Masaharu Hoshi
- The Center for Peace, Hiroshima University 1-1-89, Higashisendamachi, Naka-ku, Hiroshima-shi, Hiroshima, 730-0053, Japan.
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Abishev Z, Ruslanova B, Apbassova S, Chaizhunussova N, Shabdarbayeva D, Azimkhanov A, Zhumadilov K, Stepanenko V, Ivanov S, Shegay P, Hoshi M, Fujimoto N. Effects of Internal Exposure of Radioactive 56MnO2 Particles on the Lung in C57BL Mice. Curr Issues Mol Biol 2023; 45:3208-3218. [PMID: 37185733 PMCID: PMC10137078 DOI: 10.3390/cimb45040209] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/31/2023] [Accepted: 04/03/2023] [Indexed: 04/09/2023] Open
Abstract
The investigation of the radiation effects of the atomic bombing in Hiroshima and Nagasaki has revealed concerns about the impact of the residual radioactive dust produced in the soil. Manganese-56 is one of the major radioisotopes produced by neutrons from the bomb; hence, we previously examined the biological effects of manganese dioxide-56 (56MnO2) in Wistar rats, in which significant changes were found in the lung. In the present study, ten-week-old male C57BL mice were exposed to three doses of radioactive 56MnO2, stable MnO2 particles, or external γ-rays (2 Gy) to further examine the effects of 56MnO2 in a different species. The estimated absorbed radiation doses from 56MnO2 were 26, 96, and 250 mGy in the lung. The animals were examined at 3, 14, and 70 days post exposure. Histologically, no exposure-related changes were found in the lungs of any group. However, pulmonary mRNA expression of aquaporin 1, which is a useful marker for lung pathophysiology, was significantly elevated at 14 and 70 days, although no such changes were found in the mice exposed to external γ-rays (2 Gy). These data indicated that the inhalation exposure to 56MnO2 particles, with <250 mGy of organ doses, produced significant biological responses in the lung.
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Affiliation(s)
- Zhaslan Abishev
- Department of Pathological Anatomy and Forensic Medicine, Semey Medical University, Semey 071400, Kazakhstan
| | - Bakhyt Ruslanova
- Department of Pathological Anatomy and Forensic Medicine, Semey Medical University, Semey 071400, Kazakhstan
| | - Saulesh Apbassova
- Department of Pathological Anatomy and Forensic Medicine, Semey Medical University, Semey 071400, Kazakhstan
| | | | - Dariya Shabdarbayeva
- Department of Pathological Anatomy and Forensic Medicine, Semey Medical University, Semey 071400, Kazakhstan
| | - Almas Azimkhanov
- National Nuclear Center of the Republic of Kazakhstan, Kurchatov 071100, Kazakhstan
| | - Kassym Zhumadilov
- Department of Nuclear Physics, L.N. Gumilyov Eurasian National University, Astana 010000, Kazakhstan
| | - Valeriy Stepanenko
- A. Tsyb Medical Radiological Research Center—National Medical Research Center of Radiology, Ministry of Health of Russian Federation, 249031 Obninsk, Russia
| | - Sergey Ivanov
- A. Tsyb Medical Radiological Research Center—National Medical Research Center of Radiology, Ministry of Health of Russian Federation, 249031 Obninsk, Russia
| | - Peter Shegay
- National Medical Research Center of Radiology, Ministry of Health of the Russian Federation, 249031 Obninsk, Russia
| | - Masaharu Hoshi
- The Center for Peace, Hiroshima University, Hiroshima 730-0053, Japan
| | - Nariaki Fujimoto
- Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-0037, Japan
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Otani K, Ohtaki M, Fujimoto N, Uzbekov D, Kairkhanova Y, Saimova A, Chaizhunusova N, Habdarbaeva D, Azhimkhanov A, Zhumadilov K, Stepanenko V, Hoshi M. Effects of internal exposure to neutron-activated 56MnO2 powder on locomotor activity in rats. JOURNAL OF RADIATION RESEARCH 2022; 63:i38-i44. [PMID: 35968991 PMCID: PMC9377045 DOI: 10.1093/jrr/rrac003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 01/10/2022] [Indexed: 05/15/2023]
Abstract
At the detonation of the atomic bombing in Hiroshima and Nagasaki, a significant amount of radionuclides was produced by the neutron induced activation. The residual radiation from the explosion is crucial to the health risk of the people who entered these cities after the bombing and might have inhaled these radioactive materials. Because 56Mn is one of the major radionuclides produced in soil and have not been studied until now, we had conducted a series of experiments using rats to investigate the biological impacts of exposure of 56MnO2 particles. In these experiments, the rats' spontaneous locomotor activity was also assessed to examine the possible effects of 56Mn on their behavior. However, the locomotor activity data obtained from an individual experiment failed to identify radiation effects due to the large variation among animals and the small sample size. In the present study, all available data from our previous studies on 56MnO2 exposure (0.02-0.15 Gy of whole-body doses) as well as 60Co-γ exposure (at 2-5 Gy of whole-body doses) were pooled. Our statistical method, which takes into account individual differences and daily fluctuations, successfully identified a decrease in locomotor activity caused by 56MnO2 exposure, where the changes were gradual and reached the maximum reduction around 2 weeks after exposure. In contrast, exposure to 60Co-γ rays produced the highest decline of activity within one day. These results suggest that internal exposure to 56Mn at whole-body doses of even less than 0.15 Gy may have a long-lasting impact on locomotor activity.
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Affiliation(s)
- Keiko Otani
- Corresponding author. The Center for Peace Hiroshima University, Hiroshima, Japan; Higashisenda-machi 1-1-89, Naka-ku, Hiroshima, 730-0053, Japan.
| | - Megu Ohtaki
- The Center for Peace Hiroshima University, 730-0053, Hiroshima, Japan
- Hiroshima University, 739-8527, Japan
| | - Nariaki Fujimoto
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553, Hiroshima, Japan
| | | | | | - Aisulu Saimova
- Semey State Medical University, Semey, 071400, Kazakhstan
| | | | | | - Almas Azhimkhanov
- National Nuclear Center of the Republic of Kazakhstan, Kazakhstan, 490021, Kazakhstan
| | - Kassym Zhumadilov
- Eurasian National University named after L.N. Gumilyov, Kazakhstan, 010008, Kazakhstan
| | - Valeriy Stepanenko
- Tsyb Medical Radiological Research Center, Obninsk, 2490031, Russian Federation
| | - Masaharu Hoshi
- The Center for Peace Hiroshima University, 730-0053, Hiroshima, Japan
- Hiroshima University, 739-8527, Japan
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Stepanenko V, Sato H, Fujimoto N, Shichijo K, Toyoda S, Kawano N, Endo S, Kaprin A, Ivanov S, Shegay P, Petukhov A, Kolyzhenkov T, Bogacheva V, Chaizhunusova N, Shabdarbaeva D, Zhumadilov K, Hoshi M. External dose estimates of laboratory rats and mice during exposure to dispersed neutron-activated 56Mn powder. JOURNAL OF RADIATION RESEARCH 2022; 63:i16-i20. [PMID: 35968989 PMCID: PMC9377039 DOI: 10.1093/jrr/rrac032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 04/13/2022] [Indexed: 06/01/2023]
Abstract
Estimates of external absorbed dose in experimental animals exposed to sprayed neutron-activated 56Mn powder are necessary for comparison with internal absorbed doses estimated under the same exposure conditions, which is required for a correct interpretation of the observed biological effects. It has been established that the measured dose of external absorbed dose as a result of gamma irradiation range 1-15 mGy, which is order of magnitude less than the maximal dose of internal gamma and beta irradiation of the whole body of the same experimental animals irradiated under the same conditions: according to the available literature data, the maximal values of absorbed dose of internal gamma-beta irradiation of the whole body are in the range of 330 mGy-1200 mGy for mice and 100 mGy-150 mGy for rats. It is concluded that under the conditions of experiments with dispersed neutron-activated powder 56MnO2, internal gamma-beta irradiation of experimental animals is the main factor of radiation exposure compared to external gamma irradiation.
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Affiliation(s)
- Valeriy Stepanenko
- Corresponding author. A. Tsyb Medical Radiological Research Center – Branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation. Tel: +7 (8439) 97002;
| | - Hitoshi Sato
- Ibaraki Prefectural University of Health Sciences, 4669-2, Ami-machi, Inashiki-gun, Ibaraki 300-0394, Japan
| | - Nariaki Fujimoto
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Kazuko Shichijo
- Atomic Bomb Disease Institute, Nagasaki University, 1-12-4, Sakamoto, Nagasaki 852-8102, Japan
| | - Shin Toyoda
- Department of Applied Physics, Okayama University of Science, 1-1 Ridai, Kita-ku, Okayama 700-0005, Japan
| | - Noriyuki Kawano
- The Center for Peace, Hiroshima University, Higashisenda-machi 1-1-89, Naka-ku, Hiroshima 730-0053, Japan
| | - Satoru Endo
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi- Hiroshima 739-8527, Japan
| | - Andrey Kaprin
- National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Sergey Ivanov
- A. Tsyb Medical Radiological Research Center – Branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Peter Shegay
- National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Alexey Petukhov
- A. Tsyb Medical Radiological Research Center – Branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Timofey Kolyzhenkov
- A. Tsyb Medical Radiological Research Center – Branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Victoria Bogacheva
- A. Tsyb Medical Radiological Research Center – Branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | | | | | - Kassym Zhumadilov
- L.N. Gumilyov Eurasian National University, Munaipasova Str. 13, Nur Sultan 010008, Kazakhstan
| | - Masaharu Hoshi
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8551, Japan
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Stepanenko V, Kaprin A, Ivanov S, Shegay P, Bogacheva V, Hoshi M. Overview and analysis of internal radiation dose estimates in experimental animals in a framework of international studies of the sprayed neutron-induced 56Mn radioactive microparticles effects. JOURNAL OF RADIATION RESEARCH 2022; 63:i8-i15. [PMID: 35968992 PMCID: PMC9377035 DOI: 10.1093/jrr/rrac043] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Indexed: 06/01/2023]
Abstract
The aim of overview is to present the pooled data of published internal dose estimates and the results of corresponding analysis of internal irradiation features of experimental mice and rats after exposure to sprayed neutron activated radioactive 56MnO2. These dose estimates were conducted in a framework of multicenter international study to investigate biological effects as a result of exposure to sprayed radioactive 56MnO2 microparticles. Radionuclide 56Mn (T1/2 = 2.58 h) is one of the main gamma-beta emitters during the first hours after neutron activation of soil following nuclear explosion. It was concluded that there are three groups of organs of mice and rats, the radiation doses of which differ by approximately an order of magnitude: the group with the highest radiation doses (large and small intestine, stomach, skin and lungs), the group with lowered radiation doses (eyes, esophagus, trachea), the group with the lowest radiation doses (liver, heart, kidneys). The radiation doses to organs are proportional to the activity of the sprayed radioactive powder. The distribution of internal radiation doses among organs of experimental mice of different strains but of the same age was practically the same in case of exposure to the same activity of sprayed 56MnO2 powder. Doses of internal irradiation of experimental mice substantially exceed the doses of internal irradiation of experimental rats exposed to the same activities of the sprayed 56MnO2 powder. The data presented in the overview can be helpful for further investigation and for interpretation of the biological effects of this type of irradiation.
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Affiliation(s)
- Valeriy Stepanenko
- Corresponding author. A. Tsyb Medical Radiological Research Center – Branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation. Tel: +7 (8439) 97002; E-mail:
| | - Andrey Kaprin
- National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Sergey Ivanov
- A. Tsyb Medical Radiological Research Center – Branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Peter Shegay
- National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Viktoria Bogacheva
- A. Tsyb Medical Radiological Research Center – Branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Koroleva Str., 4., Obninsk, Kaluga Region 2490036, Russian Federation
| | - Masaharu Hoshi
- The Center for Peace, Hiroshima University, Higashi-senda-machi, Naka-ku, Hiroshima 730-0053, Japan
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Otani K, Ohtaki M, Yasuda H. Solid cancer mortality risk among a cohort of Hiroshima early entrants after the atomic bombing, 1970-2010: implications regarding health effects of residual radiation. JOURNAL OF RADIATION RESEARCH 2022; 63:i45-i53. [PMID: 35968990 PMCID: PMC9377047 DOI: 10.1093/jrr/rrac036] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/17/2022] [Indexed: 05/04/2023]
Abstract
There are two types of exposure to atomic bomb (A-bomb) radiation: exposure to initial radiation released at the time of the detonation of the bomb, and exposure to residual radiation, which remains afterwards. Health hazards caused by exposure from residual radiation have not yet been clarified. The purpose of our study was to reveal the relationships between mortality risk from solid cancer and residual radiation based on data from the early entrants to Hiroshima. It is hard to identify the individual residual radiation doses. However, these are assumed to depend on the date of entry and the entrants' behavior. Individual behavior is thought to be closely related to gender and age at exposure. We investigated a cohort of 45 809 individuals who were living in Hiroshima Prefecture on 1 January 1970 and were registered on the Database of Atomic Bomb Survivors as entrants after the bombing. Poisson regression methods were used to estimate excess relative risks (ERR) with data cross-classified by sex, age at entry, and date of entry. In males in their 20s, 30s, and 40s at entry and in females less than 10 years old and in their 40s at entry, solid cancer mortality risks were significantly higher among persons who entered the city on the day of the bombing than those who entered three or more days later. With adjustments for the age-dependent sensitivities to radiation exposure, it was extrapolated that middle-aged people who entered the city on the day of the bombing were exposed to higher levels of residual radiation than younger people.
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Affiliation(s)
- Keiko Otani
- Corresponding author. The Center for Peace, Hiroshima University, Higashisenda-machi 1-1-89, Naka-ku, Hiroshima, 730-0053, Japan.
| | - Megu Ohtaki
- The Center for Peace, Hiroshima University, Hiroshima 730-0053, Japan
- Professor Emeritus, Hiroshima University, Hiroshima 739-8511, Japan
| | - Hiroshi Yasuda
- Department of Radiation Biophysics, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8533, Japan
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Hoshi M. The overview of neutron-induced 56Mn radioactive microparticle effects in experimental animals and related studies. JOURNAL OF RADIATION RESEARCH 2022; 63:i1-i7. [PMID: 35968985 PMCID: PMC9377033 DOI: 10.1093/jrr/rrac020] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/21/2022] [Indexed: 05/28/2023]
Abstract
Investigation into the risks associated with radiation exposure has been carried out on those exposed to radiation in Hiroshima and Nagasaki, Semipalatinsk and other parts of the world. These risks are used as a guidance standard for the protection for radiation workers and the general public when exposed to radiation, and it sets upper regulatory limits for the amount of radiation exposure. However, the effects of internal exposure to radioactive microparticles have not been considered in these studies. These effects cannot be ignored since the exposure dose increases are inversely proportional to the square of the distance to the vicinity of the particles and can exceed tens of thousands of mGy. So far, only retrospective studies of people who have been exposed to radiation have been conducted, therefore we hypothesized that animal experiments would be necessary to investigate these effects. As a result, we found specific effects of radioactive microparticles. One particularly noteworthy finding was that internal exposure to radioactive microparticles resulted in pathological changes that were more than 20 times greater than those caused by the same level of external exposure. In contrast, there were other results that showed no such effects, and the reasons for this discrepancy need to be clarified. We also conducted RNA expression experiments and found that there was a difference between external exposure to 60Co gamma rays and internal exposure to 56Mn microparticles. In the future, we will need to study the mechanisms behind these findings. If the mechanism can be confirmed, it is expected to lead to the development of protective and therapeutic methods.
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Affiliation(s)
- Masaharu Hoshi
- Corresponding author. The Center for Peace, Hiroshima University, Higashisenda-machi, Naka-ku, Hiroshima 730-0053, Japan. E-mail: , , Fax: +81-82-284-6636
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Hepatic Gene Expression Changes in Rats Internally Exposed to Radioactive 56MnO 2 Particles at Low Doses. Curr Issues Mol Biol 2021; 43:758-766. [PMID: 34449546 PMCID: PMC8929078 DOI: 10.3390/cimb43020055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/12/2021] [Accepted: 07/19/2021] [Indexed: 12/14/2022] Open
Abstract
We have studied the biological effects of the internal exposure to radioactive manganese-56 dioxide (56MnO2), the major radioisotope dust found in soil after atomic bomb explosions. Our previous study of blood chemistry indicated a possible adverse effect of 56MnO2 on the liver. In the present study, we further examined the effects on the liver by determining changes in hepatic gene expressions. Male Wistar rats were exposed to 56MnO2 particles (three groups with the whole-body doses of 41, 90, and 100 mGy), stable MnO2 particles, or external 60Co γ-rays (2 Gy), and were examined together with the non-treated control group on postexposure day 3 and day 61. No histopathological changes were observed in the liver. The mRNA expression of a p53-related gene, the cyclin-dependent kinase inhibitor 1A, increased in 56MnO2 as well as in γ-ray irradiated groups on postexposure day 3 and day 61. The expression of a stress-responsive gene, nuclear factor κB, was also increased by 56MnO2 and γ-rays on postexposure day 3. However, the expression of cytokine genes (interleukin-6 or chemokine ligand 2) or fibrosis-related TGF-β/Smad genes (Tgfb1, Smad3, or Smad4) was not altered by the exposure. Our data demonstrated that the internal exposure to 56MnO2 particles at less than 0.1 Gy significantly affected the short-term gene expressions in the liver in a similar manner with 2 Gy of external γ-irradiation. These changes may be adaptive responses because no changes occurred in cytokine or TGF-β/Smad gene expressions.
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Fujimoto N, Ruslanova B, Abishev Z, Chaizhunussova N, Shabdarbayeva D, Amantayeva G, Farida R, Sandybayev M, Nagano K, Zhumadilov K, Kaprin A, Ivanov S, Stepanenko V, Hoshi M. Biological impacts on the lungs in rats internally exposed to radioactive 56MnO 2 particle. Sci Rep 2021; 11:11055. [PMID: 34040066 PMCID: PMC8155131 DOI: 10.1038/s41598-021-90443-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/16/2021] [Indexed: 01/27/2023] Open
Abstract
To understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil should be considered in addition to the initial radiation directly received from the bombs. 56Mn, which emits both β particles and γ-rays, is one of the dominant radioisotopes created in soil by neutrons from the bomb. Thus we investigated the biological effects of internal exposure to 56MnO2 particle in the lung of male Wistar rats comparing to the effects of external 60Co-γ irradiation. Absorbed doses of internal irradiation of lungs were between 25 and 65 mGy in 56MnO2-exposed animals, while the whole body doses were between 41 and 100 mGy. Animals were examined on days 3 and 61 after the exposure. There were no remarkable pathological changes related to 56MnO2 particle exposure. However, mRNA and protein expressions of aquaporin 5 increased significantly in the lung tissue on day 3 postexposure in 56MnO2 groups (by 1.6 and 2.9 times, respectively, in the highest dose group). Smad7 mRNA expression was also significantly elevated by 30% in the highest dose group of 56MnO2. Our data demonstrated that internal exposure to 56MnO2 induced significant biological responses including gene expression changes in the lungs, while external 60Co-γ irradiation of 2 Gy did not show any changes.
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Affiliation(s)
- Nariaki Fujimoto
- Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.
| | | | | | | | | | | | | | - Marat Sandybayev
- Center of Nuclear Medicine and Oncology of Semey, Semey, Kazakhstan
| | - Kasuke Nagano
- Nagano Toxicologic-Pathology Consulting, Kanagawa, Japan
| | | | - Andrey Kaprin
- National Medical Research Center of Radiology, Ministry of Health of Russian Federation, Obninsk, Russia
| | - Sergey Ivanov
- National Medical Research Center of Radiology, Ministry of Health of Russian Federation, Obninsk, Russia
| | - Valeriy Stepanenko
- National Medical Research Center of Radiology, Ministry of Health of Russian Federation, Obninsk, Russia
| | - Masaharu Hoshi
- The Center for Peace, Hiroshima University, Hiroshima, Japan
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