Ionizing radiation leads to the development of oxidative stress and damage to biologically important macromolecules (DNA, mitochondria, etc.), which in turn lead to cell death. In the case of radiotherapy, both cancer cells and normal cells are damaged. In this regard, the development of new selective antioxidants is relevant. In this study, we first investigated the redox activity of cerium oxide-pyrroloquinoline quinone nanoparticles (CeO₂@PQQ NPs) and their cytotoxic effects on normal (mouse fibroblasts, L929) and cancer (mouse adenocarcinoma, EMT6/P) cell cultures. Furthermore, the biological activity of CeO₂@PQQ NPs was evaluated in comparison with that of CeO₂ NPs and PQQ. The nanoparticles demonstrated pH-dependent reductions in the content of hydrogen peroxide after X-ray exposure. Our findings indicate that viability of EMT6/P cells was more adversely affected by CeO₂@PQQ NPs at lower concentrations (0.1 μM) compared to L929. Following X-ray irradiation at a dose of 5 Gy, significant changes in mitochondrial potential (by 29%) and decreased glutathione levels (by 32%) were also observed in EMT6/P culture following irradiation and incubation with CeO₂@PQQ NPs. Furthermore, EMT6/P exhibited a 2.5-fold increase in micronuclei and a 2-fold reduction in survival fraction compared to L929. It is hypothesized that CeO₂@PQQ NPs may exhibit selective cytotoxicity and radiosensitizing properties against EMT6/P cancer cells. The findings suggest that CeO₂@PQQ NPs may have potential as a selective redox-active antioxidant/pro-oxidant in response to X-ray radiation.

Radiation dermatitis (RD) is one of the most common side effects of radiation therapy. However, to date, there is a lack of both specific treatments for RD and validated experimental animal models with the use of various sources of ionizing radiation (IR) applied in clinical practice. The aim of this study was to develop and validate a model of acute RD induced using proton radiation in mice. Acute RD (Grade 2–4) was obtained with doses of 30, 40, and 50 Gy, either with or without depilation. The developed model of RD was characterized by typical histological changes in the skin after irradiation. Moreover, the depilation contributed to a skin histology alteration of the irradiated mice. The assessment of animal vital signs indicated that there was no effect of proton irradiation on the well-being or general condition of the animals. This model can be used to develop effective therapeutic agents and study the pathogenesis of radiation-induced skin toxicity, including that caused by proton irradiation.

The long-term space missions and helium ion (⁴He) radiotherapy require assessing of the consequences on the central nervous system. This study investigated the effects of total-body irradiation with 2 Gy helium ions on the brain of male Balb/c mice, focusing on cognitive function, microglial status, gene expression, and systemic metabolism. No statistically significant deficits in hippocampus-dependent behavior or spatial memory were detected. However, cellular and molecular alterations were detected. A decreased Iba1-positive cell density was observed at several post-irradiation time points, accompanied by morphological shifts towards a less ramified state. Gene expression analysis revealed a complex response, including a mixed neuroimmune activation profile, altered expression of redox-related genes, and downregulation of key defense genes. Metabolomics identified changes in 19 plasma metabolites consistent with alterations in energy and amino acid metabolism. Although 2 Gy did not manifest in overt cognitive impairment in the early delayed period, molecular and cellular alterations were detectable at 8 weeks, including decreased Iba1-positive cell density at several post-irradiation time points, changes in microglial morphology, altered expression of neuroimmune and redox-related genes, and systemic metabolic changes. These findings underscore the importance of multimodal assessment beyond behavioral testing in experimental models of helium-ion exposure. Because the exposure conditions used here differ from both the chronic mixed-field GCR environment and localized clinical helium-ion therapy, the results should be regarded as fundamental radiobiological observations rather than direct predictions of spaceflight or radiotherapy outcomes.