International journal of radiation biology最新文献

Purpose: To assess the protective effects of intragastric Vitamin C and N-acetylcysteine (NAC) against DNA damage from CT scan radiation in rats.

Materials and methods: The male Sprague Dawley rats (n = 8 per group) were allocated into four distinct groups: control (no CT radiation), IR (CT radiation only), Vitamin C (200 mg/kg with CT radiation), and NAC (200 mg/kg with CT radiation). Antioxidants were administered intragastrically 3 hours before scanning. Non-control groups underwent CT radiation at 120 kVp and 110 mA for 3 scans. Surface absorbed dose was measured with thermoluminescent dosimeter chips. Serum total antioxidant capacity (TAC) was measured pre- and post-scanning. γ-H2AX foci in peripheral blood lymphocytes were assessed at baseline, 1 hour, and 24 hours post-scan. Bone marrow smears were prepared 24 hours post-scan, stained with Giemsa, and micronucleus (MN) frequency in polychromatic erythrocytes was evaluated.

Results: TAC levels increased by 68.2% in the Vitamin C group and 152.3% in the NAC group compared to the IR group. γ-H2AX foci rates decreased by 10.3% in the Vitamin C group and 14.3% in the NAC group compared to the IR group. MN frequency decreased by 28.6% in the Vitamin C group and 34.9% in the NAC group compared to the IR group. No significant difference was found between Vitamin C and NAC.

Conclusion: Oral Vitamin C and NAC significantly mitigate radiation exposure from CT imaging in rats. Both antioxidants effectively reduce γ-H2AX foci and micronucleus formation, offering substantial protection against radiation-induced DNA damage.

Purpose: The current work investigates the potential of exopolysaccharides (EPSs) and carotenoids produced from radioresistant bacteria as radioprotective agents.

Materials and methods: Twenty strains, isolated from gamma-irradiated roots of Cistanche violacea from Chott El-Djerid (Tunisia), were screened for EPSs and carotenoids production. The most EPS and carotenoids-producing bacterium was selected. The assessment of the impact of UVC-radiation dose effects on the synthesis of EPSs and carotenoids was investigated by response surface methodology (RSM). Both EPS and Carotenoids, from the strain CV6, were characterized by UV-Vis and Fourier transform infrared. The radioprotective potential of EPS and carotenoids on the survival of K. rosea CV6 following UVC dose was evaluated using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay. Finally, in silico analyses of CV6's genome were assessed to identify the mechanisms involved in UVC protection.

Results: It was demonstrated that UVC irradiation of Kocuria rosea CV6 generated high amounts of EPSs and a carotenoid-producing strain. The assessment of the impact of radiation dose effects on the synthesis of EPSs and carotenoids by RSM shows that strain CV6 exhibited particular resistance to UVC radiation. The characterization of EPSs revealed the presence of six particular functional groups using Fourier transform infrared spectra. Pigments produced by CV6 were classified as carotenoids based on their spectroscopic characteristics. Also, the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide survival assay demonstrated a positive correlation between the concentrations of EPSs and carotenoids and viability of the UV-sensitive strain, Escherichia coli DH5α, following exposure to UVC radiation. In addition, the whole-genome analysis of the CV6 strain identified seven biosynthetic gene clusters encoding secondary metabolites, including those involved in the synthesis of EPSs and carotenoids.

Conclusion: The present investigation demonstrated that EPSs and carotenoids, extracted from K. rosea CV6, are promising bioactive components that could be used in the protection against UVC radiation.

Background: Ionizing radiation (IR) disrupts redox balance and causes tissue injury through reactive oxygen species. Although the Nrf2-ARE pathway governs antioxidant defense, effective radioprotective activators remain limited. Hinokitiol, a natural antioxidant and anti-inflammatory tropolone, has not been previously evaluated in vivo for Nrf2-mediated radioprotection.

Methods: Forty male albino rats were divided into four groups: control, irradiated (8 Gy, fractionated), hinokitiol-only, and hinokitiol-pretreated + irradiated (Hinokitiol (10 mg/kg/day), by oral gavage). All parameters were assessed 24 hours after the final irradiation session.

Results: IR caused marked hematological suppression (reductions in RBCs, WBCs, platelets), hepatocellular injury (elevated ALT, reduced total protein), oxidative stress (increased MDA, NO, MPO), apoptosis, and downregulation of Nrf2-dependent genes. Hinokitiol pretreatment partially restored hematological parameters (platelets improved by over 20%, p = 0.026), reduced ALT by more than half, lowered NO and MPO levels, restored GSH, SOD, and CAT activities by more than 60% (p < 0.001), and decreased DNA fragmentation by nearly 50% (p < 0.01). Gene expression analysis revealed significant (p < 0.01) upregulation of Ho-1 , Nqo1, and Txnrd1 and significant (p < 0.01) suppression of Nf-κB and Tnf-α, consistent with Nrf2-ARE pathway activation and attenuation of inflammatory signaling. Histological analysis confirmed preserved hepatic architecture, supporting the liver's sensitivity to systemic oxidative injury and highlighting Hinokitiol's hepatic accumulation and protective effects.

Conclusion: These findings suggest, for the first time, that hinokitiol may activate the Nrf2-ARE pathway to counteract IR-induced oxidative stress, inflammation, and apoptosis, resulting in systemic protection. Hinokitiol emerges as a promising radioprotective candidate, warranting further investigation into its pharmacokinetics, toxicity profile, and translational potential as an adjunct in radiotherapy and other radiation exposure scenarios.

Purpose: This study investigates the therapeutic potential of copper-doped carbon quantum dots (Cu-CQDs), integrating photothermal and photodynamic approaches to enhance cancer treatment efficacy.

Materials and methods: Cu-CQDs were synthesized using citric acid via a hydrothermal method. Nanoparticle characterization was conducted using dynamic light scattering (DLS), spectrofluorometry, and UV-Vis spectrophotometry. Photothermal performance was assessed by measuring temperature increases under laser irradiation. Photodynamic activity was evaluated by oxidative activity detection (consistent with reactive oxygen species (ROS) production) with 2,7-dichlorofluorescein diacetate. Cytotoxicity was examined against MCF-7 breast cancer cells, with and without the addition of 5-aminolevulinic acid (5-ALA) as a photosensitizer.

Results: The Cu-CQDs demonstrated a fluorescence quantum yield of 2.96%. Upon laser irradiation at 25 mg/mL, the temperature rose above 60 °C within 10 minutes, indicating effective photothermal performance. The cytotoxicity of the synthesized nanotherapeutic against MCF-7 cancer cells was evaluated, revealing that the combined photothermal and photodynamic effects (CQD + 5-ALA+LASER) resulted in 65% cell viability, which was significantly different from the cell viability obtained with the photothermal effect alone (CQD+LASER).

Conclusions: The study presents a promising cancer treatment strategy by combining photothermal and photodynamic effects of Cu-CQDs. This dual-function approach may serve as an effective method for future cancer therapies.

Objective: Radioactive iodine (RAI) is widely used for the diagnosis and treatment of thyroid diseases. Common side effects of RAI include sialadenitis, xerostomia and gastrointestinal symptoms. In this study we aimed to investigate the effect of Saccharomyces boulardii (S.boulardii) on the gastrointestinal changes induced by RAI.

Methods: Twenty four Wistar albino rats were grouped into three; the first group received RAI, the second group received RAI together with S.boulardii (RAI-S) and the third group served as controls. Tissue oxidative stress parameters and zonulin levels-as a marker of increased intestinal permeability- were measured at the end of the study. The gastrointestinal tissue specimens are also microscopically analyzed and graded according to the Histological Activity Index (HAI).

Results: We found no difference in the zonulin levels. We detected no difference in oxidative stress parameters in most of the tissues except slight changes in duodenum and ileum. HAI scores were significantly lower in RAI-S group when compared to the RAI group.

Conclusion: This study showed that S.boulardii is protective against RAI induced gastrointestinal damage. This effect is probably beyond its antioxidant properties or impacts on intestinal permeability.

Introduction: Cancer risks of radiation are commonly made to evaluate an increase in mortality or incidence of cancers above background levels in subjects of the same age. However, the increased risk can also be evaluated by assuming a dose-dependent earlier onset expressed by a parallel shift of the mortality or incidence rate toward younger ages, which eventually results in life shortening.

Methods: Organ-specific relative risks for cancer was estimated by assuming that exposure to radiation increases the risk due to tissue reactions which subsequently facilitate an earlier onset of naturally occurring cancers. In this case, the years of earlier onset X can be obtained by examining the equation showing that the mortality or incidence rate for all cancers at age 70 in the 1 Gy-exposed group equals the rate at age 70 + X in the control group. In the present study, assuming that the X can be applied to all organs, organ-specific relative risk (RR)/Gy values were calculated as the ratio of the mortality or incidence rate at age 70 + X vs. at age 70 in the control group.

Results and discussion: The RR/Gy values thus obtained agreed closely with the epidemiologically estimated RR/Gy in major organs (stomach, colon, lung, liver etc.) while no clear evidence for an increased risk has been observed in the Life Span Study of atomic bomb survivors for pancreas, gallbladder, and kidney although the age-related patterns for the incidence or mortality of the control subjects are similar to those for the major organs. Possible reasons for the discrepancy are discussed.

Introduction: Radiation-induced brain injury causes significant neurotoxicity and cognitive dysfunction in patients undergoing radiotherapy for brain tumors. This study aimed to evaluate the neuroprotective effects of intranasal ketamine on radiation-induced brain injury, specifically focusing on its modulation of perineuronal networks (PNNs), extracellular matrix components, and neuroinflammation.

Materials and methods: Eighteen male New Zealand White Rabbits were divided into three groups: normal controls, irradiation (IR) with saline (IR + saline), and IR with ketamine (IR + ketamine). Whole-brain IR (20 Gy) was applied to the IR groups, and ketamine (2 mg/kg/day) was administered intranasally for 15 days. Biochemical markers, including malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), brain-derived neurotrophic factor (BDNF), ADAMTS4, and syndecan-1 levels, were measured. Histopathological analysis of hippocampal and cerebellar regions assessed neuronal survival and astrogliosis. Magnetic resonance spectroscopy (MRS) evaluated lactate and N-acetylaspartate (NAA) levels, reflecting metabolic and neuronal integrity.

Results: Ketamine administration significantly reduced oxidative stress (MDA) and inflammatory markers (TNF-α) while restoring BDNF levels compared to the IR + saline group. ADAMTS4 and syndecan-1 levels were reduced, changes consistent with PNN-associated extracellular matrix dynamics, but without direct confirmation by core PNN markers such as aggrecan or WFA staining. Histopathology showed increased neuronal survival and decreased reactive astrogliosis in ketamine-treated groups. ¹H-MRS provided supporting evidence for metabolic changes (↓lactate, ↑NAA) consistent with improved mitochondrial function and neuronal integrity.

Conclusion: Intranasal ketamine demonstrates significant neuroprotective effects in a radiation-induced brain injury model by reducing oxidative stress and inflammation, modulating extracellular matrix components, and preserving neuronal integrity. These findings highlight ketamine's potential as a therapeutic agent, although direct PNN markers and broader cytokine panels were not assessed. Overall, ketamine showed neuroprotective effects across biochemical, histological, and MRS-supported metabolic readouts.

Purpose: The transgenerational effects of preconception parental radiation exposure in humans remain unclear. We assessed genomic integrity in adult children of British nuclear test (NT) veterans-a community that has expressed long-standing concerns about adverse health effects, including in their offspring-to investigate for any constitutional chromosomal abnormalities and/or cytogenetic indicators of genomic instability that might be associated with paternal participation at NT sites.

Materials and methods: Peripheral blood samples were obtained from 86 adult children (45 from nuclear test (NT) and 41 control), all born to veterans from the British Army, Royal Air Force, or Royal Navy.

Results: G-banded karyotyping revealed no constitutional chromosomal abnormalities in any NT sample, including those from families reporting adverse health outcomes. We next assessed for unstable aberrations using conventional Giemsa staining and found some evidence of instability. Specifically, a small subset of NT children (N = 4) showed elevated chromatid aberration frequencies (7.81 ± 4.01 per 100 cells) compared with controls (4.36 ± 0.62; N = 26). To investigate further, we analyzed matched veteran father-child pairs observing a weak association between fathers' unstable aberration burden and chromatid aberrations in their children, suggesting a potential transgenerational effect. This positive trend was most pronounced in the small group of families (N = 8; 2 control and 6 NT) previously identified as being enriched for mutation signature SBS16 in the germline.

Conclusions: Although based on a small sample size, this observation warrants further investigation to understand the significance of SBS16, if any, including whether it may serve as a potential transgenerational mutational signature of radiation exposure. Overall, and in the context of health concerns raised by NT families, none of the self-reported health-related variables showed any association with unstable aberration burden in either the veteran fathers or their adult children.

Purpose: Magnetic resonance (MR)-guided radiotherapy (MRgRT) is an attractive treatment option for many patients with cancer, allowing higher radiation doses to be safely delivered. However, even with more precise tumor targeting and higher doses, hypoxia remains an important clinical challenge, making tumors more radioresistant and detracting from the benefits of dose escalation. Nanoparticles loaded with manganese dioxide (MnO₂) have been developed as theranostic agents to improve MRgRT. We review the MR-enhancing and oxygen-generating properties of MnO₂ nanoparticles, the evidence that MnO₂ nanoparticles can improve tumor response to RT, and the opportunities for further research to support translation into the clinic.

Conclusion: The theranostic potential of MnO₂ nanoparticles lies in the dual functionality of providing tumor-specific MR enhancement for RT planning and image guidance, while also generating oxygen in the tumor microenvironment (TME) to overcome hypoxia-induced radioresistance. Several preclinical studies have demonstrated lower levels of hypoxia and improved tumor response when RT is combined with MnO₂ nanoparticles. In addition, MnO₂ nanoparticles have been reported to deplete intracellular antioxidants and create an immunogenic, less immunosuppressive TME, which may also enhance radiotherapy efficacy. These encouraging findings support further clinical evaluation in patients receiving MRgRT.

Objective: This position paper results from an International Union of Radioecology symposium aimed at identifying challenges to develop eco-centric and holistic approaches to understanding ionizing radiation impacts on ecosystems. An ecosystem approach is particularly relevant today not only because of the triple planetary crisis of climate change, biodiversity loss, and pollution, which make single-stressor approaches unrealistic, but because of renewed interest in nuclear power as a potential solution to transition away from fossil fuels. For example, there are proposals to site small modular reactors in remote and pristine areas. The focus of the symposium was to expand the boundaries of existing approaches in radioecology and look at issues like ecosystem complexity and multiple stressors, which complicate single-stressor approaches.

Conclusions: Discussion centered around existing tools for radiation protection e.g. Adverse Outcome Pathway (AOP) analysis, biomarkers, use of microcosms and mesocosms and modeling approaches. These approaches were discussed with emphasis on identifying gaps, boundaries, and where leaps into the unknown might be beneficial. Identified challenges with biomarker and AOP approaches were that the individual level is generally addressed while interrelatedness of ecosystem components is difficult to capture. Novel ideas suggested were to construct multiple-stressor AOPs which capture key interactions and consider time as a critical component, or to exploit 'ecological network analysis' metrics which have been extensively used in ecological science. Other discussions centered on complexity and chaos modeling. The use of microcosms, focused field studies, and harnessing ecosystem information and communication systems were suggested to bridge the gap between individual and population-level responses.