Preconception X-ray alters offspring mtDNA in mice
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- Hokkaido University researchers exposed adult male and female mice to a single dose of X-ray radiation before mating, producing four groups including irradiated fathers, irradiated mothers, both parents irradiated, and controls.
- Offspring brain mtDNA copy number decreased when only the father had been exposed to radiation, according to the study published in Redox Biology in March 2026.
- Offspring liver mtDNA copy number decreased when only the mother was irradiated, while no significant changes appeared in the heart in any exposure group.
- Exposed parent mice showed increased mtDNA copy numbers in their own blood, a marker the authors describe as a sensitive indicator of cellular stress following radiation.
- Lower liver mtDNA in offspring was associated with increased liver weight and body weight, suggesting mitochondrial regulation may play a role in neonatal organ growth.
- Corresponding author Hisanori Fukunaga framed the finding as evidence that mitochondria represent an additional route through which environmental stresses like ionizing radiation can be transmitted to the next generation.
- The research team noted the mtDNA changes may reflect a dynamic, potentially reversible response rather than a permanent genetic mutation, which could shape how such effects are assessed clinically.
Why it matters: The study identifies a previously underappreciated pathway for intergenerational radiation effects—mitochondrial rather than nuclear DNA—and shows the impact is parent-of-origin and organ-specific in mice. For radiation protection guidelines aimed at people of reproductive age, this suggests mtDNA copy number could become a useful biomarker for tracking exposure consequences in offspring, though the authors stress the effect may be reversible and the work has not yet been replicated in humans.
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