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Updated: Aug 19, 2026
Loss- and Gain-of-function Approach to Investigate Early Cell Fate Determinants in Preimplantation Mouse Embryos
Published on: June 6, 2016
Combined application of misonidazole and piotron pions on mouse embryos
Abstract:
Mouse embryos on day 8 of gestation were irradiated with negative pions (12.5-100 rad) or 200 kV X-rays (12.5-150 rad). Misonidazole (MISO), a hypoxic cell radiosensitizer, was applied 30 min before exposure. On day 13 the fetuses were examined for lethality, growth retardation and malformation. No significant embryolethal effects were observed after irradiation alone in the dose range of 12.5-100 rad (X-rays or pions). However, MISO alone and in combination with radiation led to high rates of lethality. The frequency of growth retardation was significantly increased at 100 rad and in combined treatments at low radiation doses. MISO and irradiation with 50 rad and more induced complex damages consisting of multiple and severe malformations and growth retardation. The relative biological effectiveness (RBE) for teratogenic effects was 1.6. In conclusion, the combined application of MISO and radiation of different LET revealed a strong enhancing action compared to single treatments. The extent of enhancement depends on both radiation quality and dose.
Insights
Misonidazole (MISO) combined with radiation significantly increased embryo lethality and developmental issues in mice. Even low radiation doses enhanced by MISO caused severe malformations and growth retardation.
Area of Science:
- Radiation biology
- Developmental toxicology
- Radiobiology
Background:
- Misonidazole (MISO) is a hypoxic cell radiosensitizer used to enhance radiation therapy effectiveness.
- Understanding the teratogenic effects of combined radiation and MISO is crucial for assessing risks in pregnant individuals undergoing radiation treatment.
Purpose of the Study:
- To evaluate the embryolethal, growth retarding, and teratogenic effects of negative pions and X-rays alone and in combination with Misonidazole (MISO) in mouse embryos.
- To determine the relative biological effectiveness (RBE) for teratogenic effects.
Main Methods:
- Day 8 pregnant mice were exposed to negative pions (12.5-100 rad) or 200 kV X-rays (12.5-150 rad), with or without Misonidazole (MISO) administered 30 minutes prior.
- Fetuses were examined on day 13 for lethality, growth retardation, and malformations.
Main Results:
- Misonidazole (MISO) alone and in combination with radiation significantly increased fetal lethality.
- Growth retardation was elevated at 100 rad and in combined treatments at lower radiation doses.
- MISO combined with 50 rad or more induced severe, complex malformations and growth retardation, with an RBE of 1.6 for teratogenic effects.
Conclusions:
- Combined application of MISO and radiation demonstrates a strong synergistic effect on embryonic development, exceeding the impact of single treatments.
- The enhancement of radiation's teratogenic effects by MISO is dependent on radiation quality and dose.
- These findings highlight the increased risk of developmental abnormalities when MISO is used concurrently with radiation therapy.
