Novel use of zebrafish as a vertebrate model to screen radiation protectors and sensitizers

Abstract

Purpose/ObjectiveZebrafish (Danio rerio) embryos provide a unique vertebrate model to screen therapeutic agents, because of their closer genetic relationship to humans than yeast or insects, ready abundance and accessibility, and optical transparency throughout their brief development. We have evaluated the effects of ionizing radiation and screened known radiation modifiers using zebrafish embryos.Materials/MethodsWildtype zebrafish adults were mated, and viable embryos collected and plated for exposure to doses of 0–10 Gy single-fraction 250 kVp X-rays in the presence or absence of either the radioprotective thiophosphate Amifostine (0–4 mM) or the radiosensitizing EGFR inhibitor AG1478 (0–10 μM) at various stages of embryonic development from 1–24 hours post fertilization (hpf). Dechorionated embryos were examined for morphologic abnormalities and viability up to 144 hpf.ResultsIonizing radiation alone produced a time-and dose-dependent perturbation of normal development and survival of exposed embryos with maximal sensitivity detected at doses ≥4 Gy delivered prior to midblastula transition (4 hpf). This effect was attenuated by pre-incubation with Amifostine, while pretreatment with AG1478 enhanced teratogenicity and lethality, particularly at therapeutically relevant (2–4 Gy) doses of radiation.ConclusionsThese data validate the use of zebrafish as a vertebrate model to assess the effect of ionizing radiation alone as well as in the presence of modulators of the radiation response. Zebrafish embryos may thus provide a rapid, facile system to screen novel agents ultimately intended for human use in the context of therapeutic or accidental radiation exposure Purpose/ObjectiveZebrafish (Danio rerio) embryos provide a unique vertebrate model to screen therapeutic agents, because of their closer genetic relationship to humans than yeast or insects, ready abundance and accessibility, and optical transparency throughout their brief development. We have evaluated the effects of ionizing radiation and screened known radiation modifiers using zebrafish embryos. Zebrafish (Danio rerio) embryos provide a unique vertebrate model to screen therapeutic agents, because of their closer genetic relationship to humans than yeast or insects, ready abundance and accessibility, and optical transparency throughout their brief development. We have evaluated the effects of ionizing radiation and screened known radiation modifiers using zebrafish embryos. Materials/MethodsWildtype zebrafish adults were mated, and viable embryos collected and plated for exposure to doses of 0–10 Gy single-fraction 250 kVp X-rays in the presence or absence of either the radioprotective thiophosphate Amifostine (0–4 mM) or the radiosensitizing EGFR inhibitor AG1478 (0–10 μM) at various stages of embryonic development from 1–24 hours post fertilization (hpf). Dechorionated embryos were examined for morphologic abnormalities and viability up to 144 hpf. Wildtype zebrafish adults were mated, and viable embryos collected and plated for exposure to doses of 0–10 Gy single-fraction 250 kVp X-rays in the presence or absence of either the radioprotective thiophosphate Amifostine (0–4 mM) or the radiosensitizing EGFR inhibitor AG1478 (0–10 μM) at various stages of embryonic development from 1–24 hours post fertilization (hpf). Dechorionated embryos were examined for morphologic abnormalities and viability up to 144 hpf. ResultsIonizing radiation alone produced a time-and dose-dependent perturbation of normal development and survival of exposed embryos with maximal sensitivity detected at doses ≥4 Gy delivered prior to midblastula transition (4 hpf). This effect was attenuated by pre-incubation with Amifostine, while pretreatment with AG1478 enhanced teratogenicity and lethality, particularly at therapeutically relevant (2–4 Gy) doses of radiation. Ionizing radiation alone produced a time-and dose-dependent perturbation of normal development and survival of exposed embryos with maximal sensitivity detected at doses ≥4 Gy delivered prior to midblastula transition (4 hpf). This effect was attenuated by pre-incubation with Amifostine, while pretreatment with AG1478 enhanced teratogenicity and lethality, particularly at therapeutically relevant (2–4 Gy) doses of radiation. ConclusionsThese data validate the use of zebrafish as a vertebrate model to assess the effect of ionizing radiation alone as well as in the presence of modulators of the radiation response. Zebrafish embryos may thus provide a rapid, facile system to screen novel agents ultimately intended for human use in the context of therapeutic or accidental radiation exposure These data validate the use of zebrafish as a vertebrate model to assess the effect of ionizing radiation alone as well as in the presence of modulators of the radiation response. Zebrafish embryos may thus provide a rapid, facile system to screen novel agents ultimately intended for human use in the context of therapeutic or accidental radiation exposure