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Photon hormesis deactivates alpha-particle induced bystander effects between zebrafish embryos. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2016.12.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Ng CYP, Cheng SH, Yu KN. Effect of Photon Hormesis on Dose Responses to Alpha Particles in Zebrafish Embryos. Int J Mol Sci 2017; 18:E385. [PMID: 28208665 PMCID: PMC5343920 DOI: 10.3390/ijms18020385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/03/2017] [Accepted: 02/08/2017] [Indexed: 01/23/2023] Open
Abstract
Photon hormesis refers to the phenomenon where the biological effect of ionizing radiation with a high linear energy transfer (LET) value is diminished by photons with a low LET value. The present paper studied the effect of photon hormesis from X-rays on dose responses to alpha particles using embryos of the zebrafish (Danio rerio) as the in vivo vertebrate model. The toxicity of these ionizing radiations in the zebrafish embryos was assessed using the apoptotic counts at 20, 24, or 30 h post fertilization (hpf) revealed through acridine orange (AO) staining. For alpha-particle doses ≥ 4.4 mGy, the additional X-ray dose of 10 mGy significantly reduced the number of apoptotic cells at 24 hpf, which proved the presence of photon hormesis. Smaller alpha-particle doses might not have inflicted sufficient aggregate damages to trigger photon hormesis. The time gap T between the X-ray (10 mGy) and alpha-particle (4.4 mGy) exposures was also studied. Photon hormesis was present when T ≤ 30 min, but was absent when T = 60 min, at which time repair of damage induced by alpha particles would have completed to prevent their interactions with those induced by X-rays. Finally, the drop in the apoptotic counts at 24 hpf due to photon hormesis was explained by bringing the apoptotic events earlier to 20 hpf, which strongly supported the removal of aberrant cells through apoptosis as an underlying mechanism for photon hormesis.
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Affiliation(s)
- Candy Yuen Ping Ng
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China.
| | - Shuk Han Cheng
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China.
- State Key Laboratory in Marine Pollution, City University of Hong Kong, Hong Kong, China.
| | - Kwan Ngok Yu
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China.
- State Key Laboratory in Marine Pollution, City University of Hong Kong, Hong Kong, China.
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Kong EY, Cheng SH, Yu KN. Zebrafish as an In Vivo Model to Assess Epigenetic Effects of Ionizing Radiation. Int J Mol Sci 2016; 17:ijms17122108. [PMID: 27983682 PMCID: PMC5187908 DOI: 10.3390/ijms17122108] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/01/2016] [Accepted: 12/09/2016] [Indexed: 12/14/2022] Open
Abstract
Exposure to ionizing radiations (IRs) is ubiquitous in our environment and can be categorized into “targeted” effects and “non-targeted” effects. In addition to inducing deoxyribonucleic acid (DNA) damage, IR exposure leads to epigenetic alterations that do not alter DNA sequence. Using an appropriate model to study the biological effects of radiation is crucial to better understand IR responses as well as to develop new strategies to alleviate exposure to IR. Zebrafish, Danio rerio, is a scientific model organism that has yielded scientific advances in several fields and recent studies show the usefulness of this vertebrate model in radiation biology. This review briefly describes both “targeted” and “non-targeted” effects, describes the findings in radiation biology using zebrafish as a model and highlights the potential of zebrafish to assess the epigenetic effects of IR, including DNA methylation, histone modifications and miRNA expression. Other in vivo models are included to compare observations made with zebrafish, or to illustrate the feasibility of in vivo models when the use of zebrafish was unavailable. Finally, tools to study epigenetic modifications in zebrafish, including changes in genome-wide DNA methylation, histone modifications and miRNA expression, are also described in this review.
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Affiliation(s)
- Eva Yi Kong
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China.
| | - Shuk Han Cheng
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China.
- State Key Laboratory in Marine Pollution, City University of Hong Kong, Hong Kong, China.
| | - Kwan Ngok Yu
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, China.
- State Key Laboratory in Marine Pollution, City University of Hong Kong, Hong Kong, China.
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Hu M, Hu N, Ding D, Zhao W, Feng Y, Zhang H, Li G, Wang Y. Developmental toxicity and oxidative stress induced by gamma irradiation in zebrafish embryos. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2016; 55:441-450. [PMID: 27582010 DOI: 10.1007/s00411-016-0663-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 08/18/2016] [Indexed: 06/06/2023]
Abstract
This study aimed to evaluate the biological effects of gamma irradiation on zebrafish embryos. Different doses of gamma rays (0.01, 0.05, 0.1, 0.5 and 1 Gy) were used to irradiate zebrafish embryos at three developmental stages (stage 1, 6 h post-fertilization (hpf); stage 2, 12 hpf; stage three, 24 hpf), respectively. The survival, malformation and hatching rates of the zebrafish embryos were measured at the morphological endpoint of 96 hpf. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were assayed. Morphology analysis showed that gamma irradiation inhibited hatching and induced developmental toxicity in a dose-dependent manner. Interestingly, after irradiation the malformation rate changed not only in a dose-dependent manner but also in a developmental stage-dependent manner, indicating that the zebrafish embryos at stage 1 were more sensitive to gamma rays than those at other stages. Biochemical analysis showed that gamma irradiation modulated the activities of antioxidant enzymes in a dose-dependent manner. A linear relationship was found between GPx activity and irradiation dose in 0.1-1 Gy group, and GPx was a suitable biomarker for gamma irradiation in the dose range from 0.1 to 1 Gy. Furthermore, the activities of SOD, CAT, GR and GPx of the zebrafish embryos at stage 3 were found to be much higher than those at other stages, indicating that the zebrafish embryos at stage 3 had a greater ability to protect against gamma rays than those at other stages, and thus the activities of antioxidant enzymes changed in a developmental stage-dependent manner.
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Affiliation(s)
- Miao Hu
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, Hunan Province, China
| | - Nan Hu
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, Hunan Province, China
| | - Dexin Ding
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, Hunan Province, China.
| | - Weichao Zhao
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, Hunan Province, China
| | - Yongfu Feng
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, Hunan Province, China
| | - Hui Zhang
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, Hunan Province, China
| | - Guangyue Li
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, Hunan Province, China
| | - Yongdong Wang
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, 421001, Hunan Province, China
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Shahmohammadi Beni M, Krstic D, Nikezic D, Yu KN. A calibration method for realistic neutron dosimetry in radiobiological experiments assisted by MCNP simulation. JOURNAL OF RADIATION RESEARCH 2016; 57:492-498. [PMID: 27380801 PMCID: PMC5045084 DOI: 10.1093/jrr/rrw063] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/23/2016] [Accepted: 05/09/2016] [Indexed: 06/06/2023]
Abstract
Many studies on biological effects of neutrons involve dose responses of neutrons, which rely on accurately determined absorbed doses in the irradiated cells or living organisms. Absorbed doses are difficult to measure, and are commonly surrogated with doses measured using separate detectors. The present work describes the determination of doses absorbed in the cell layer underneath a medium column (DA) and the doses absorbed in an ionization chamber (DE) from neutrons through computer simulations using the MCNP-5 code, and the subsequent determination of the conversion coefficients R (= DA/DE). It was found that R in general decreased with increase in the medium thickness, which was due to elastic and inelastic scattering. For 2-MeV neutrons, conspicuous bulges in R values were observed at medium thicknesses of about 500, 1500, 2500 and 4000 μm, and these were attributed to carbon, oxygen and nitrogen nuclei, and were reflections of spikes in neutron interaction cross sections with these nuclei. For 0.1-MeV neutrons, no conspicuous bulges in R were observed (except one at ~2000 μm that was due to photon interactions), which was explained by the absence of prominent spikes in the interaction cross-sections with these nuclei for neutron energies <0.1 MeV. The ratio R could be increased by ~50% for small medium thickness if the incident neutron energy was reduced from 2 MeV to 0.1 MeV. As such, the absorbed doses in cells (DA) would vary with the incident neutron energies, even when the absorbed doses shown on the detector were the same.
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Affiliation(s)
- Mehrdad Shahmohammadi Beni
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | | | - Dragoslav Nikezic
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong Faculty of Science, University of Kragujevac, Serbia
| | - Kwan Ngok Yu
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
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Ng CYP, Cheng SH, Yu KN. Hormetic effect induced by depleted uranium in zebrafish embryos. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 175:184-191. [PMID: 27060238 DOI: 10.1016/j.aquatox.2016.03.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 03/12/2016] [Accepted: 03/26/2016] [Indexed: 06/05/2023]
Abstract
The present work studied the hormetic effect induced by uranium (U) in embryos of zebrafish (Danio rerio) using apoptosis as the biological endpoint. Hormetic effect is characterized by biphasic dose-response relationships showing a low-dose stimulation and a high-dose inhibition. Embryos were dechorionated at 4h post fertilization (hpf), and were then exposed to 10 or 100μg/l depleted uranium (DU) in uranyl acetate solutions from 5 to 6 hpf. For exposures to 10μg/l DU, the amounts of apoptotic signals in the embryos were significantly increased at 20 hpf but were significantly decreased at 24 hpf, which demonstrated the presence of U-induced hormesis. For exposures to 100μg/l DU, the amounts of apoptotic signals in the embryos were significantly increased at 20, 24 and 30 hpf. Hormetic effect was not shown but its occurrence between 30 and 48 hpf could not be ruled out. In conclusion, hormetic effect could be induced in zebrafish embryos in a concentration- and time-dependent manner.
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Affiliation(s)
- C Y P Ng
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong
| | - S H Cheng
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong; State Key Laboratory in Marine Pollution, City University of Hong Kong, Hong Kong.
| | - K N Yu
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong; State Key Laboratory in Marine Pollution, City University of Hong Kong, Hong Kong.
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Ng CYP, Kong EY, Kobayashi A, Suya N, Uchihori Y, Cheng SH, Konishi T, Yu KN. Non-induction of radioadaptive response in zebrafish embryos by neutrons. JOURNAL OF RADIATION RESEARCH 2016; 57:210-219. [PMID: 26850927 PMCID: PMC4915534 DOI: 10.1093/jrr/rrv089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/13/2015] [Accepted: 11/03/2015] [Indexed: 06/05/2023]
Abstract
In vivo neutron-induced radioadaptive response (RAR) was studied using zebrafish (Danio rerio) embryos. The Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility at the National Institute of Radiological Sciences (NIRS), Japan, was employed to provide 2-MeV neutrons. Neutron doses of 0.6, 1, 25, 50 and 100 mGy were chosen as priming doses. An X-ray dose of 2 Gy was chosen as the challenging dose. Zebrafish embryos were dechorionated at 4 h post fertilization (hpf), irradiated with a chosen neutron dose at 5 hpf and the X-ray dose at 10 hpf. The responses of embryos were assessed at 25 hpf through the number of apoptotic signals. None of the neutron doses studied could induce RAR. Non-induction of RAR in embryos having received 0.6- and 1-mGy neutron doses was attributed to neutron-induced hormesis, which maintained the number of damaged cells at below the threshold for RAR induction. On the other hand, non-induction of RAR in embryos having received 25-, 50- and 100-mGy neutron doses was explained by gamma-ray hormesis, which mitigated neutron-induced damages through triggering high-fidelity DNA repair and removal of aberrant cells through apoptosis. Separate experimental results were obtained to verify that high-energy photons could disable RAR. Specifically, 5- or 10-mGy X-rays disabled the RAR induced by a priming dose of 0.88 mGy of alpha particles delivered to 5-hpf zebrafish embryos against a challenging dose of 2 Gy of X-rays delivered to the embryos at 10 hpf.
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Affiliation(s)
- Candy Y P Ng
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Ave., Kowloon Tong, Hong Kong
| | - Eva Y Kong
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Ave., Kowloon Tong, Hong Kong
| | - Alisa Kobayashi
- Research, Development and Support Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Noriyoshi Suya
- Research, Development and Support Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
| | - Yukio Uchihori
- Research, Development and Support Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
| | - Shuk Han Cheng
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Ave., Kowloon Tong, Hong Kong State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Ave., Kowloon Tong, Hong Kong
| | - Teruaki Konishi
- Research, Development and Support Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
| | - Kwan Ngok Yu
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Ave., Kowloon Tong, Hong Kong State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Ave., Kowloon Tong, Hong Kong
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