Marr, Bryan2025-02-272025-02-272025-02-27http://hdl.handle.net/10393/50219https://doi.org/10.20381/ruor-30950This study investigates the effects of sustained low dose ionizing radiation (LDIR) exposure on the murine immune system, focusing on the molecular mechanisms and cellular responses to low dose rate whole-body 𝛾-radiation. Female C57BL/6 mice were continuously exposed to low dose rate 60Co 𝛾-radiation over a period of 7 days, resulting in cumulative absorbed doses of 10 mGy and 100 mGy. Immediately following the exposure period, hematological analysis, flow cytometry, bulk RNA-sequencing, and single-cell RNA-sequencing were employed to comprehensively assess immune cell populations and their gene expression profiles. Our findings indicate that the LDIR exposure model employed induced, at most, minimal perturbations to the immune system. Hematological metrics showed no significant changes in the abundance of hematopoietic cells in blood. Flow cytometry revealed no significant differences in the proportion of immune cell subsets in the spleen, thymus, and bone marrow across radiation conditions. Transcriptomic analyses identified minimal differentially expressed genes of low magnitude. Unsupervised single-cell RNA-seq analysis further confirmed the absence of significant perturbations to immune cell transcriptomes. These results suggest a preservation of immune cell homeostasis under sustained low dose-rate exposure conditions. This study represents the first single-cell transcriptomic investigation of immune cells following whole-body exposure to low dose ionizing radiation. It contributes to a broader understanding of radiation biology, emphasizing that the effects of low-dose radiation on the immune system can be limited at very low dose-rates in mice. These findings may inform future research on radiation exposure and contribute to assessing the risks associated with chronic low-dose radiation in various contexts, from medical treatments to occupational exposures.enImmunologyLow-Dose RadiationIonizing RadiationThesis