International journal of radiation biology最新文献

Background: Radiation induces pronounced and widespread histopathological damage in the testes, which exhibit a high degree of radiosensitivity; consequently, the utilization of effective radioprotective agents has become increasingly crucial for mitigating radiation-associated toxic outcomes, particularly infertility.

Purpose: The present investigation aimed to comprehensively evaluate the capacity of selenium-L-methionine to mitigate radiation-induced histopathological and molecular alterations within testicular tissue, thereby assessing its potential as a radioprotective agent.

Material and methods: Rats were randomized into four groups: Group 1 (control), Group 2 (rad group), which received a single 10 Gy irradiation on day 2; Group 3 (sel group), which received intraperitoneal selenium-L-methionine (4 mg/kg) for six consecutive days; and Group 4 (rad+sel group), which received the same selenium-L-methionine regimen followed by 10 Gy irradiation 30 minutes after the second day's administration. On the seventh day, all animals were euthanized, and testicular tissue and blood samples were collected for biochemical and histopathological analyses.

Results: In the testicular tissues of the radiation-exposed groups, deformed and abnormal seminiferous tubule structures, a reduction in germ cell numbers, and sloughing of tubular epithelial cells were observed. Seminiferous tubule diameters, Johnsen's testicular biopsy scores, epididymal sperm motility, and the expression levels of Connexin 43, HSP70, PCNA, StAR, CAT, and SOD were decreased in the irradiated group, whereas TGFB1, IL-6, and MMP9 levels were increased. Selenium-L-methionine treatment largely reversed these radiation-induced changes.

Conclusions: The addition of selenium-L-methionine to radiotherapy yielded promising radioprotective outcomes, and this therapeutic effect positions selenium-L-methionine as a potential novel radioprotective agent. Furthermore, the immunohistochemical markers used in the study-including MMP9, Connexin 43, HSP70, PCNA, and StAR served as sensitive indicators for detecting radiation-induced damage in testicular tissue. Nevertheless, larger-scale and long-term studies are required to validate these findings and to further substantiate the potential use of selenium-L-methionine as a radioprotective agent in clinical practice.

Purpose: In order to estimate the effect of radiation exposure on the workers of a uranium enterprise, teeth samples were collected for EPR dosimetry of tooth enamel from workers of uranium mines living in Shantobe settlement (Akmola region, Northern Kazakhstan) and from residents of this settlement who had never worked in the mine as a control.

Methods: The accumulated radiation doses in enamel were estimated based on the magnitude of the radiation-induced EPR signal in the samples. Excess (additional) doses were obtained after subtracting the contribution of natural radiation at typical levels during enamel age, and they were interpreted as caused by radiation in the work environment and by radioactive contamination of the territory.

Results: For the personnel of the uranium mining enterprise (17 teeth samples), the average excess dose was 90 ± 20 mGy (standard uncertainty of the average is indicated here and below). For the rest of the population who did not work at the mine (10 teeth samples), the average excess dose is estimated at 20 ± 12 mGy.

Conclusions: A higher mean dose and greater variation were observed for miners in comparison to non-mining people in the same settlement. These differences were likely due to the occupational exposure.

Background: When the same energy is delivered to a cellular target, DNA damage and the resulting cellular response may vary depending on the density and distribution pattern of the energy delivered to the critical volume of each cell. DNA damage can be quantitated based on the pattern of dose distribution over the sub-micrometer volumes in nucleus. DNA double-strand breaks (DSBs) are considered the most critical events for cellular effects. Local effect model (LEM), DNA damage model (DDM), and Giant LOop Binary LEsion (GLOBLE) model have been used to predict cell survival under radiation exposure.

Purpose: This study aims to implement computational modeling for prediction of cell survival under radiation exposure, by quantitating radiation events on cellular targets, such as local energy deposition and DSB production, in a unified frame. The conceptual bases of LEM, DDM, and GLOBLE model were adopted to derive parameters for radiation events.

Methods: The physics models of Geant4-DNA were used to simulate the interactions of X-rays and alpha particles with bio-matter. Cell nucleus was modeled to be a collection of ${(540\hspace{0.17em}\text{nm})}^3$ sub-volumes. Statistical variation of energy deposition to individual sub-volumes was analyzed to count DSB production and DSB multiplicity. Cell surviving fractions (SFs) were calculated by LEM based on the distribution of local doses to sub-volumes and by DDM and GLOBLE model based on the DSB production and their potential interactions in sub-volumes. Model parameters were derived by fitting the models to experimental data for rat diencephalon (RD) cells and rat gliosarcoma (RG) cells.

Results and conclusions: The overkill effect was reflected in the models based on LEM and DDM by employing threshold local dose and threshold number of DSBs in sub-volumes, respectively. Results suggest that the number of sub-volumes impacted with DSBs rather than the DSB multiplicity within individual sub-volumes would be better parameter to predict cell killing effect, which complies with the GLOBLE model.

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.

Purpose: This study aimed to investigate oxidative stress and histopathological changes in healthy rats after oral administration of I-131, to elucidate the mechanisms of gastrointestinal mucosal injury associated with radioiodine exposure, and provide translational insights relevant to clinical radioiodine therapy.

Materials and methods: Twenty-seven rats received I-131 (9.62 × 10⁶ Bq/100 µL) orally. Observations were made up to 7 days post-administration. Oxidative stress levels in the thyroid, small intestine, and stomach were measured using an enzyme-linked immunosorbent assay, while histopathological changes were analyzed using hematoxylin-eosin staining. Data were analyzed using one-way analysis of variance (SPSS v25).

Results and conclusion: Biochemical assays showed mild and inconsistent variations in antioxidant enzyme activity. H₂O₂ levels remained stable, whereas thyroid SOD activity exhibited a transient ∼22-fold increase within the first hour before returning to baseline by day 7, with no corresponding elevation in CAT or GPx. Histopathological evaluation revealed marked mucosal injury in the small intestine, characterized by epithelial erosion, edema, and inflammatory infiltration within 30 min, peaking at 2-3 h, and partially reappearing on days 5-7. In contrast, gastric lesions were milder and resolved completely by day 7. The discrepancy between biochemical stability and pronounced tissue injury suggests that localized oxidative stress may occur despite unchanged bulk reactive oxygen species levels, likely due to rapid compensatory antioxidant responses in healthy tissues. Overall, these findings underscore the importance of integrating biochemical and histological endpoints for a comprehensive assessment of radiation-induced toxicity. This integrated approach also supports further investigation into lipid peroxidation, protein oxidation, glutathione redox status, and mitochondrial function to elucidate the mechanisms underlying radioiodine-induced oxidative stress.

Purpose: The aim of this study was to investigate the modulation of hippocampal Schaffer-CA1 synaptic LTP by broad-band mixed-frequency micro-magnetic stimulation (μMS), to break through the limitations of traditional single-frequency stimulation, and to explore the potential of multi-frequency synergistic effect on cognitive function enhancement.

Materials and methods: A μMS system was constructed on a flexible PCB using a micro-coil (0402 size, 1 μH) to generate single-frequency and mixed-frequency magnetic fields. The signal was synthesized by Gnuradio, and the magnetic field strength of around 2 mT was output via a power amplifier. LTP was induced by applying high-frequency electrical stimulation to isolated hippocampal slices of Sprague-Dawley rats, and after the intervention with μMS, field excitatory postsynaptic potentials (fEPSPs) were recorded using the MEA2100 and analyzed for the modulation effect on LTP.

Results: Single-frequency stimulation showed frequency-dependent modulation: 70 kHz significantly enhanced LTP (57%, p < .05) and 1 kHz inhibited LTP (-38%, p < .05). Broadband mixed-frequency stimulation showed synergistic effects: the high-frequency band (50-90 kHz) enhanced LTP (33%, p < .05), and the high and low-frequency mixed-band (1-1.4 kHz + 50-70 kHz) enhanced LTP (27%, p < .05), and the experimental success rate was higher than that of single-frequency stimulation (36% vs 21%). The lower frequency band (500-1400 Hz) inhibited LTP (-27%, p < .05).

Conclusion: Wide-band mixed-frequency μMS has frequency-dependent modulation of LTP, high-frequency mixed-frequency stimulation has an enhancement effect, low-frequency mixed-frequency stimulation has an inhibitory effect, while high and low-frequency mixed-frequency stimulation reflect high-frequency enhancement characteristics and improve the stability of LTP modulation, which provides an experimental basis for cross-frequency and multi-scale neuromodulation.

Purpose: This mini-review aims to synthesize current knowledge regarding radiation-induced effects on female fertility and reproductive capacity, and to identify knowledge gaps relevant to radiation protection.

Methods: We critically examined evidence from developmental biology, animal models, clinical studies, and epidemiological investigations. Key topics include germ cell and follicle biology, radiation dose thresholds, therapeutic exposures, and environmental and occupational contexts.

Results: Female germ cells are highly radiosensitive, with animal models indicating a mean lethal dose as low as 0.05-0.15 Gy in primordial oocytes. In humans, pelvic irradiation increases risks of acute ovarian failure, premature ovarian insufficiency, and infertility, depending on dose and age at exposure. Cranial irradiation further impairs fertility through damage to the hypothalamic-pituitary axis. In contrast, evidence from occupational and environmental exposures is scarce, with most studies addressing miscarriage or perinatal outcomes rather than infertility itself.

Conclusions: While advances in oncofertility research have clarified therapeutic risks, systematic data on environmental and occupational exposures are lacking. Strengthened prospective studies and integration of fertility-specific biomarkers are urgently needed to inform comprehensive radiation protection strategies.

Purpose: This study assesses the radiological impact of radionuclide dispersion for the first four days after a hypothetical nuclear accident scenario, utilizing the HotSpot Health Physics software developed by the Lawrence Livermore National Laboratory (LLNL).

Materials and methods: A Gaussian plume model was used to estimate the dispersion of I-131 and Cs-137 under various atmospheric conditions.

Results: The study's key findings include an analysis of the Total Effective Dose Equivalent (TEDE) along a simulated contamination plume, highlighting the impact of atmospheric stability on radiation levels. It also assesses the radiobiological risks, noting that young people and women are especially vulnerable, as the risk of thyroid or leukemia may vary by a factor of 10⁴ depending on location and atmospheric stability conditions. The analysis also indicated that the TEDE generated by the inventory release could range from 0.1 to 10 Sv of whole-body exposure within the first 10 km downwind under stable atmospheric conditions.

Conclusions: Even minor fluctuations in TEDE caused by local atmospheric stability can significantly affect the estimated risks of thyroid cancer and leukemia. This may alter the logistical resources required and the epidemiological methods used to identify and prioritize concerns. Implementing environmental monitoring and strategies such as distributing stable iodine and enforcing dietary restrictions during the initial phases of nuclear emergencies may be guided by risk assessments based on simulations.

Purpose: Radiation exposure can lead to acute radiation syndrome and systemic inflammation, highlighting the need for accessible tests to assess exposure and its biological effects. This study investigated changes in inflammatory markers derived from CBC in male Wistar rats exposed to total-body irradiation with 6 MV LINAC photons delivered at doses of 6 Gy and 8 Gy, at a dose rate of 200 cGy/min.

Methods: A total of 42 rats were randomized into eight groups: control, sham, and irradiated groups. These groups were evaluated at 0-, 24-, and 48-hours post-exposure. Blood samples were analyzed for standard CBC values and derived ratios, such as the NLR (Neutrophil-to-Lymphocyte Ratio), PLR (Platelet-to-Lymphocyte Ratio), MLR (Monocyte-to-Lymphocyte Ratio), HLR (Hemoglobin-to-Lymphocyte Ratio), PMR (Platelet-to- Monocyte Ratio), SII (Systemic Immune-Inflammation Index), and SIRI (Systemic Inflammatory Response Index).

Results: Two-way ANOVA revealed significant time-dependent increases in NLR, PLR, HLR, and SII (p < .001 for all), independent of the radiation dose. MLR and PMR showed significant effects related to both time and dose, with higher values observed at 24-48 hours post-exposure.

Conclusion: Our results indicate that the duration following irradiation influences most ratio-based indices, which appear to be sensitive in detecting early responses to radiation effects. This makes them rapid and cost-effective methods for monitoring radiation injury.

Background: In radiotherapy (RT), the dose given to the organs at risk (OAR) is as important as the dose received by the tumor. FF (Flattening Filtered) and FFF (Flattening Filter Free) treatment techniques used in RT offer different advantages in terms of their effects on target and critical organs. Treatment duration varies depending on the number of monitor units (MU) delivered per unit time. The aim of this study was to investigate biochemically and histopathologically the damage in healthy laryngeal tissue exposed to 600 MU/min FF and 2400 MU/min FF ionizing radiation under different fractionation protocols. Also to investigate the radioprotective effect of melatonin against the radiological damage.

Methods: The 78 rats included in the study were divided into 10 groups. Control and melatonin-only groups did not receive RT. The other 8 groups received FF and FFF ionizing radiation in different dose fractions. Half of the radiation group received melatonin 15 min before RT.

Results: No histological and biochemical differences were observed in the control and MLT only groups. Radiobiological damage was statistically significantly lower in the RT+MLT group compared to the RT only group.

Conclusions: It has been observed that melatonin has a protective effect against tissue damage caused by radiation exposure in healthy laryngeal tissue.