Dose-dependent Changes After Proton and Photon Irradiation in a Zebrafish Model

Area of Science:

• Radiobiology
• Oncology
• Biomedical research

Background:

• Hadron therapy, particularly proton therapy, is increasingly vital in cancer management.
• Accurate detection of biological effects is crucial for optimizing radiation treatments.
• Vertebrate models offer valuable insights into radiation biology.

Purpose of the Study:

• To refine the detection of biological effects from proton beam radiation.
• To compare the biological impact of proton beams versus photon beams.
• To establish a vertebrate model for radiobiological characterization.

Main Methods:

• Irradiation of zebrafish embryos (24 and 72 h postfertilization) with a 150 MeV proton beam (entrance plateau and Bragg peak) and reference photons.
• Evaluation of radiation-induced DNA double-strand breaks (DSB) and histopathological changes in the eye, muscles, and brain.
• Quantification of organ-specific deterioration (eye, yolk sac, body).

Main Results:

• Proton beams induced more and longer-lasting DNA double-strand breaks (DSB) in eye and muscle cells compared to photon beams.
• Observed histopathological changes included edema, necrosis, and tissue disorganization, particularly in the eye.
• Dose-dependent morphological deteriorations were noted at ≥10 Gy, with relative biological effectiveness (RBE) ranging from 0.99±0.07 to 1.12±0.19.

Conclusions:

• Quantitative assessment of radiation-induced changes in zebrafish embryos is effective for radiobiological characterization.
• Zebrafish embryos serve as a suitable model for evaluating the biological effects of proton therapy.
• Findings contribute to a better understanding of proton beam radiobiology for cancer treatment.