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Limited Immune Perturbations in Mice Exposed to Sustained Low-Dose Ionizing Radiation

ABSTRACT: The effects of high-dose ionizing radiation (HDIR) exposure on the immune system are largely understood with consensus, yet there remains a fragmented understanding of the impact of low-dose ionizing radiation (LDIR) on immune homeostasis, especially in sustained exposure conditions. This study investigates the effects of continuous LDIR exposure on the murine immune system, focusing on transcriptomic responses and cellular perturbations following low-dose-rate whole-body -radiation. Female 18-week-old C57BL/6 mice were continuously exposed to low-dose-rate 60Co radiation over a period of 7 days, resulting in cumulative absorbed doses of 10 mGy and 100 mGy. Our findings indicate that the LDIR exposure induced, at most, only minimal transcriptomic perturbations to the immune system in C57BL/6 mice. These results suggest a preservation of immune cell homeostasis under the sustained low-dose-rate exposure conditions studied. It contributes to a broader understanding of radiation biology, emphasizing that the effects of LDIR on the immune system can be limited at low-dose-rates in mice.

ORGANISM(S): Mus musculus

PROVIDER: GSE296450 | GEO | 2026/04/14

REPOSITORIES: GEO

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Project description:Following nuclear accidents and the increasing use of radionuclides, environmental radiation radiological protection is a source of major concern, particularly in the context of low doses. Ionizing radiation (IR) may lead to genetic mutations, chromosomal rearrangements and epigenetic modifications. The present study focuses on the in vivo effects of low to moderate doses of IR on zebrafish early embryonic development. The effects of IR on the transcriptome were studied at the shield stage (6 hours post-fertilization, hpf) and at dose rates from 50 mGy/h to 0.005 mGy/h. The effects on the methylome by whole genome bisulfite sequencing were investigated at the same stage and at dose rates of 50 mGy/h and 5 mGy/h.IR exposure impacted the expression of genes involved in germ layers specification during gastrulation of zebrafish embryos. Moreover, changes in mitochondrial energetic metabolism were detected at all dose rates. Different transcriptomic responses were observed between groups irradiated at the two highest dose rates, 50 mGy/h and 5 mGy/h and those irradiated at the three lower dose rates. However, the transcriptomic analysis revealed an impact of IR on development, neurogenesis and muscular development at 50 mGy/h, 5 mGy/h and 0.5 mGy/h. The global level of methylation was not changed after exposure to IR, and no widespread changes in transposable elements were detected. Rather, we observed that IR induced loci specific demethylation in the promoter of genes involved in development, neurogenesis and myogenesis. Interestingly, this promoter hypomethylation was equally associated with a change in gene expression. In this study, both DMR and gene expression analysis pointed toward a specific deregulation of genes involved in development, neurogenesis and myogenesis. The modification of the methylation pattern in promoters of genes involved in central nervous system development and muscle development seems to be responsible of transcriptomic changes. This study confirms previous results obtained at later developmental stages, showing that neurogenesis and muscle development were also impacted at 50 mGy/h, 5 mGy/h and 0.5 mGy/h with phenotypic alterations in terms of muscle histology and swimming behaviour. This suggests that early developmental perturbations are predictive of functional defects at later developmental stages.

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Limited Immune Perturbations in Mice Exposed to Sustained Low-Dose Ionizing Radiation

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