Neutrons do not produce a bystander effect in zebrafish irradiated in vivo

Wang, Chu; Smith, Richard; Duhig, John; Prestwich, W.V.; Byun, S.H.; McNeill, Fiona E.; Seymour, Colin; Mothersill, Carmel

doi:10.3109/09553002.2011.584939

Cited by 21 publications

(17 citation statements)

References 53 publications

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“…radiation (Salbu et al, 2008;Smith et al, 2011), as radiation types found to induce a bystander effect in fish. Neutrons have a direct effect on zebrafish but do not induce a bystander effect (Wang et al, 2011). The shift, with time, from a pro-to anti-apoptotic bystander effect and then back to a pro-apoptotic effect on HPV-G reporter cells (as seen here) could suggest the existence of a precise mechanism in bystander effect induction.…”

Section: Discussionmentioning

confidence: 50%

“…Previously this assay has been shown to strongly correlate with apoptosis related bcl-2 and cmyc expression (Mothersill et al, 2007;Smith et al, 2011). In addition bcl-2 and cmyc expression in cells from irradiated and bystander fish explants has been shown to mirror bcl-2 and cmyc expression in HPV-G cells (Mothersill et al, 2009) and apoptotic bodies in irradiated fish explant cells mirrors HPV-G survival (Wang et al, 2011).…”

Section: Discussionmentioning

confidence: 95%

“…The methods for inducing a bystander effect, the collection of tissue samples and the Human Papilloma Virus strain G transfected human keratinocytes (HPV-G) reporter cell clonogenic assay, for determining the induction of a pro-or anti-apoptotic effect, in fish of this size, have all been previously described (Mothersill et al, 2007(Mothersill et al, , 2009(Mothersill et al, , 2012Saroya et al, 2010;Smith et al, 2011;Wang et al, 2011). Briefly, groups of 4 injected fish were placed in one side of a mesh partitioned container.…”

Section: Bystander Effect Induction Tissue Collection and Clonogenicmentioning

confidence: 99%

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Short and long term bystander effect induction by fathead minnows (Pimephales promelas, Rafinesque, 1820) injected with environmentally relevant whole body doses of 226Ra

Smith

Seymour

Mothersill

2013

Journal of Environmental Radioactivity

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Section: Discussionmentioning

confidence: 50%

Section: Discussionmentioning

confidence: 95%

Section: Bystander Effect Induction Tissue Collection and Clonogenicmentioning

confidence: 99%

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Short and long term bystander effect induction by fathead minnows (Pimephales promelas, Rafinesque, 1820) injected with environmentally relevant whole body doses of 226Ra

Smith

Seymour

Mothersill

2013

Journal of Environmental Radioactivity

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“…Most bystander effect studies have been performed using x-rays [22], [24], [29], gamma rays [17], [35], [53] and alpha particles [47], [54], [55], however, little has been done concerning the effects of neutron radiation [56]. Such information might be important for risk estimation in response to neutron exposure.…”

Section: Introductionmentioning

confidence: 99%

“…No conclusive cytogenetic evidence exists to support or refute the existence of non-targeted effects in cellular responses to neutrons. A bystander effect following neutron exposure has been observed in Chinese hamster ovary cells [57], but no effect was seen in zebrafish irradiated in vivo [56]. There are no available cytogenetic data concerning the bystander effect in human cells in response to neutrons.…”

Section: Introductionmentioning

confidence: 99%

Neutron Exposures in Human Cells: Bystander Effect and Relative Biological Effectiveness

et al. 2014

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Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy), and irradiated-cell conditioned media (ICCM) was transferred to unirradiated cells. The cytokinesis-block micronucleus assay was used to quantify genetic damage in radiation-naïve cells exposed to ICCM from cultures that received 0 (control), 0.5, 1, 1.5, 2, 3 or 4 Gy neutrons. Cells grown in ICCM from irradiated cells showed no significant increase in the frequencies of micronuclei or nucleoplasmic bridges compared to cells grown in ICCM from sham irradiated cells for either cell line. However, the neutron beam has a photon dose-contamination of 5%, which may modulate a neutron-induced bystander effect. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. No significant increase in the frequencies of micronuclei or bridges was observed at these doses of photons for either cell line when cultured in ICCM. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (p<0.0001). These data indicate that neutrons do not induce a bystander effect in these cells. Finally, neutrons had a relative biological effectiveness of 2.0±0.13 for micronuclei and 5.8±2.9 for bridges compared to cobalt-60. These results may be relevant to radiation therapy with fast neutrons and for regulatory agencies setting standards for neutron radiation protection and safety.

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Developmental toxicity and oxidative stress induced by gamma irradiation in zebrafish embryos

Ding

et al. 2016

Radiat Environ Biophys

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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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Neutrons do not produce a bystander effect in zebrafish irradiated in vivo

Abstract: The results confirm in vitro experiments which suggest neutrons do not induce bystander signaling. In fact they may suppress gamma induced signaling suggesting a possible intriguing new and as yet unclear mechanism.

Cited by 21 publications

References 53 publications

Short and long term bystander effect induction by fathead minnows (Pimephales promelas, Rafinesque, 1820) injected with environmentally relevant whole body doses of 226Ra

Short and long term bystander effect induction by fathead minnows (Pimephales promelas, Rafinesque, 1820) injected with environmentally relevant whole body doses of 226Ra

Neutron Exposures in Human Cells: Bystander Effect and Relative Biological Effectiveness

Developmental toxicity and oxidative stress induced by gamma irradiation in zebrafish embryos

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