Adaptive response in zebrafish embryos induced using microbeam protons as priming dose and X-ray photons as challenging dose. (original) (raw)
Related papers
Ultrahigh-Dose-Rate Proton Irradiation Elicits Reduced Toxicity in Zebrafish Embryos
Advances in Radiation Oncology
Purpose: Recently, ultrahigh-dose-rate radiation therapy (UHDR-RT) has emerged as a promising strategy to increase the benefit/risk ratio of external RT. Extensive work is on the way to characterize the physical and biological parameters that control the so-called "Flash" effect. However, this healthy/tumor differential effect is observable in in vivo models, which thereby drastically limits the amount of work that is achievable in a timely manner. Methods and Materials: In this study, zebrafish embryos were used to compare the effect of UHDR irradiation (8-9 kGy/s) to conventional RT dose rate (0.2 Gy/s) with a 68 MeV proton beam. Viability, body length, spine curvature, and pericardial edema were measured 4 days postirradiation. Results: We show that body length is significantly greater after UHDR-RT compared with conventional RT by 180 mm at 30 Gy and 90 mm at 40 Gy, while pericardial edema is only reduced at 30 Gy. No differences were obtained in terms of survival or spine curvature. Conclusions: Zebrafish embryo length appears as a robust endpoint, and we anticipate that this model will substantially fasten the study of UHDR proton-beam parameters necessary for "Flash."
Feasibility of proton FLASH effect tested by zebrafish embryo irradiation
Radiotherapy and Oncology, 2019
Background and purpose: Motivated by first animal trials showing the normal tissue protecting effect of electron and photon Flash irradiation, i.e. at mean dose rates of 100 Gy/s and higher, relative to conventional beam delivery over minutes the feasibility of proton Flash should be assessed. Materials and methods: A setup and beam parameter settings for the treatment of zebrafish embryo with proton Flash and proton beams of conventional dose rate were established at the University Proton Therapy Dresden. Zebrafish embryos were treated with graded doses and the differential effect on embryonic survival and the induction of morphological malformations was followed for up to four days after irradiation. Results: Beam parameters for the realization of proton Flash were set and tested with respect to controlled dose delivery to biological samples. Analyzing the dose dependent embryonic survival and the rate of spinal curvature as one type of developmental abnormality, no significant influence of proton dose rate was revealed. For the rate of pericardial edema as acute radiation effect, a significant difference (p < 0.05) between proton Flash and protons delivered at conventional dose rate of 5 Gy/min was observed for one dose point only. Conclusion: The feasibility of Flash proton irradiation was successfully shown, whereas more experiments are required to confirm the presence or absence of a protecting effect and to figure out the limits and requirements for the Flash effect.
Radiobiological effects and proton RBE determined by wildtype zebrafish embryos
PLOS ONE, 2018
The increasing use of proton radiotherapy during the last decade and the rising number of long-term survivors has given rise to a vital discussion on potential effects on normal tissue. So far, deviations from clinically applied generic RBE (relative biological effectiveness) of 1.1 were only obtained by in vitro studies, whereas indications from in vivo trials and clinical studies are rare. In the present work, wildtype zebrafish embryos (Danio rerio) were used to characterize the effects of plateau and mid-SOBP (spread-out Bragg peak) proton radiation relative to that induced by clinical MV photon beam reference. Based on embryonic survival data, RBE values of 1.13 ± 0.08 and of 1.20 ± 0.04 were determined four days after irradiations with 20 Gy plateau and SOBP protons relative to 6 MV photon beams. These RBE values were confirmed by relating the rates of embryos with morphological abnormalities for the respective radiation qualities and doses. Besides survival, the rate of spine bending, as one type of developmental abnormality, and of pericardial edema, as an example for acute radiation effects, were assessed. The results revealed that independent on radiation quality both rates increased with time approaching almost 100% at the 4 th day post irradiation with doses higher than 15 Gy. To sum up, the applicability of the zebrafish embryo as a robust and simple alternative model for in vivo characterization of radiobiological effects in normal tissue was validated and the obtained RBE values are comparable to previous finding in animal trials.
Dose-dependent Changes After Proton and Photon Irradiation in a Zebrafish Model
Anticancer Research, 2020
Background/Aim: The importance of hadron therapy in the cancer management is growing. We aimed to refine the biological effect detection using a vertebrate model. Materials and Methods: Embryos at 24 and 72 h postfertilization were irradiated at the entrance plateau and the mid spread-out Bragg peak of a 150 MeV proton beam and with reference photons. Radiation-induced DNA doublestrand breaks (DSB) and histopathological changes of the eye, muscles and brain were evaluated; deterioration of specific organs (eye, yolk sac, body) was measured. Results: More and longer-lasting DSBs occurred in eye and muscle cells due to proton versus photon beams, albeit in different numbers. Edema, necrosis and tissue disorganization, (especially in the eye) were observed. Dose-dependent morphological deteriorations were detected at ≥10 Gy dose levels, with relative biological effectiveness between 0.99±0.07 (length) and 1.12±0.19 (eye). Conclusion: Quantitative assessment of radiation induced changes in zebrafish embryos proved to be beneficial for the radiobiological characterization of proton beams.
A feasibility study of zebrafish embryo irradiation with laser-accelerated protons
Review of Scientific Instruments, 2020
The development from single shot basic laser plasma interaction research toward experiments in which repetition rated laser-driven ion sources can be applied requires technological improvements. For example, in the case of radio-biological experiments, irradiation duration and reproducible controlled conditions are important for performing studies with a large number of samples. We present important technological advancements of recent years at the ATLAS 300 laser in Garching near Munich since our last radiation biology experiment. Improvements range from target positioning over proton transport and diagnostics to specimen handling. Exemplarily, we show the current capabilities by performing an application oriented experiment employing the zebrafish embryo model as a living vertebrate organism for laser-driven proton irradiation. The size, intensity, and energy of the laser-driven proton bunches resulted in evaluable partial body changes in the small (<1 mm) embryos, confirming the feasibility of the experimental system. The outcomes of this first study show both the appropriateness of the current capabilities and the required improvements of our laser-driven proton source for in vivo biological experiments, in particular the need for accurate, spatially resolved single bunch dosimetry and image guidance.
Cancer Research, 2006
The zebrafish (Danio rerio) has emerged as a popular vertebrate model system for cancer and treatment-related research. Benefits include ease of care, rapid development, optical clarity of embryos, which allows visualization of major organ systems, and opportunities for genetic manipulation. However, specific parameters of radiation sensitivity have not been systematically documented. We investigated the effects of radiation and a radiomodifier on zebrafish viability and embryonic development. Embryos were exposed to ;-radiation (5, 10, or 20 Gy) at sequential times postfertilization and serially assessed for viability and morphologic abnormalities. As expected, lethality and morphologic perturbations were more pronounced earlier in embryogenesis and with higher radiation doses and were partially reversed by amifostine. The effects of radiation and concurrent treatment with amifostine on the developmental organization of the eye and brain were striking. Radiation resulted in hypocellularity and disorganization of the cellular layers of the retina, effects partially reversed by amifostine, as well as lens opacification. Radiation strikingly reduced the volume of brain, but the volume loss was substantially blocked by amifostine. Increased terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling signal was noted in both the irradiated eye and brain, but reduced by amifostine. Finally, irradiating embryos resulted in caspase activation detectable in 96-well microplates, which was proportional to the number of embryos and radiation dose; the degree of activation was markedly reduced by amifostine. These results together suggest the power and versatility of the zebrafish in assessing the effects of radiation and radiomodifiers on organ and tissue development. (Cancer Res 2006; 66(16): 8172-81)
International Journal of Radiation Biology, 2018
Purpose: The recent rapid increase of hadron therapy applications requires the development of high performance, reliable in vivo models for preclinical research on the biological effects of high linear energy transfer (LET) particle radiation. Aim: The aim of this paper was to test the relative biological effectiveness (RBE) of the zebrafish embryo system at two neutron facilities. Material and Methods: Series of viable zebrafish embryos at 24-hour post-fertilization (hpf) were exposed to single fraction, whole-body, photon and neutron (reactor fission neutrons (<En ¼ 1 MeV>) and (p (18 MeV)þBe, ¼ 3.5 MeV) fast neutron) irradiation. The survival and morphologic abnormalities of each embryo were assessed at 24-hour intervals from the point of fertilization up to 192 hpf and then compared to conventional 6 MV photon beam irradiation results. Results: The higher energy of the fast neutron beams represents lower RBE (ref. source LINAC 6 MV photon). The lethality rate in the zebrafish embryo model was 10 times higher for 1 MeV fission neutrons and 2.5 times greater for p (18 MeV)þBe cyclotron generated fast neutron beam when compared to photon irradiation results. Dose-dependent organ perturbations (shortening of the body length, spine curvature, microcephaly, micro-ophthalmia, pericardial edema and inhibition of yolk sac resorption) and microscopic (marked cellular changes in eyes, brain, liver, muscle and the gastrointestinal system) changes scale together with the dose response. Conclusion: The zebrafish embryo system is a powerful and versatile model for assessing the effect of ionizing radiation with different LET values on viability, organ and tissue development.
Environmental Toxicology and Chemistry, 2011
The effects of radiation on biological systems have been studied for many years, and it is now accepted that direct damage to DNA from radiation is the triggering event leading to biological effects. In the present study, DNA damage induced by acute or chronic irradiation was compared at the cellular (zebrafish [Danio rerio] cell line ZF4) and developmental (embryo) levels. Zebrafish ZF4 cells and embryos (at 3 h postfertilization) were exposed within ranges of acute doses (0.3-2 Gy/d) or chronic dose rates (0.1-0.75 Gy/d). DNA damage was assessed by immunodetection of g-H2AX and DNA-PK (DNA double-strand breaks) and the alkaline comet assay (DNA single-strand breaks). Zebrafish embryo development and DNA damage were examined after 120 h. At low doses, chronic irradiation induced more residual DNA damage than acute irradiation, but embryo development was normal. From 0.3 Gy, a hyperradiosensitivity phenomenon compared to other species was shown for acute exposure with an increase of DNA damage, an impairment of hatching success, and larvae abnormalities. These results suggest a dose-dependent correlation between unrepaired DNA damage and abnormalities in embryo development, supporting the use of DNA repair proteins as predictive biomarkers of ionizing radiation exposure. This could have important implications for environmental protection. Environ. Toxicol. Chem.