Cancer mortality in workers at risk of occupational exposure to ionizing radiation in a company in the nuclear sector headquarters in São Paulo / Mortalidade por câncer em trabalhadores com risco de exposição ocupacional à radiação ionizante em empresa do setor nuclear sediada em São Paulo

ABSTRACT Objective: To compare cancer mortality among workers exposed to gamma and X radiation and the general population of the city of São Paulo, as well as that of the subgroup monitored with those not monitored for gamma and X radiation in a work unit with ionizing radiation based in the city of São Paulo. Methods: Between 2016 and 2021, a retrospective open cohort study was carried out with workers who were employed from 08/31/1956 to 12/31/2016 based on data collected at the company and in official institutions. Standardized mortality ratios (SMR) were calculated by sex, age and calendar period of cancers grouped according to type, risk factor and organ system in two analyses: in the external analysis, the mortality of the study population was compared with that of the general population of the city of São Paulo; In the internal analysis, the mortality of the monitored subgroup was compared with that of the subgroup not monitored for gamma and X radiation. Results: The external mortality analysis showed SMR=0.224 (95%CI 0.208-0.240) and the healthy worker effect, while the internal mortality analysis showed SMR=0.685 (95%CI 0.618-0.758). Conclusion: This study showed lower cancer mortality among exposed workers when compared to mortality in the general population and the healthy worker effect. Among workers monitored for gamma and X radiation, cancer mortality was lower when compared to those not monitored.

RESUMO Objetivo: Comparar a mortalidade por câncer entre trabalhadores expostos à radiação gama e X e a população geral do município de São Paulo, bem como a do subgrupo monitorado com o não monitorado para radiação gama e X em uma unidade de trabalho sediada no município de São Paulo. Métodos: Entre 2016 e 2021 foi realizado estudo de coorte aberta retrospectiva com trabalhadores que tiveram vínculo empregatício desde 31/08/1956 até 31/12/2016 a partir de dados coletados na empresa e em instituições oficiais. Foram calculadas as razões de mortalidade padronizadas (RMP) por sexo, idade e período calendário de cânceres agrupados segundo o tipo, o fator de risco e o sistema orgânico em duas análises: na análise externa, comparou-se a mortalidade da população de estudo com a da população geral do município de São Paulo; já na análise interna, comparou-se a mortalidade do subgrupo monitorado com a do subgrupo não monitorado para radiação gama e X. Resultados: A análise externa de mortalidade mostrou RMP=0,224 (IC95% 0,208-0,240) e o efeito do trabalhador sadio, enquanto a análise interna de mortalidade mostrou RMP = 0,685 (IC95% 0,618-0,758). Conclusão: Este estudo mostrou menor mortalidade por câncer entre os trabalhadores expostos quando comparada com a mortalidade da população geral e o efeito do trabalhador sadio. Entre os trabalhadores monitorados para radiação gama e X, a mortalidade por câncer foi menor quando comparada com a dos não monitorados.

Dimethyl fumarate inhibits NLRP3/AIM2 inflammasomes to prevent spleen radiation injury ZHANG / 中国药理学通报

Aim To investigate the protective effect of dimethyl fumarate on spleen injury induced by gamma radiation in mice and the related mechanism. Methods C57BL/6 mice were randomly divided into the blank control group, radiation model group and DMF administration group, which were administered once at 12 h before irradiation and once at 0. 5 h, 12 h, 24 h and 48 h after irradiation. The 30-day survival rate, body weight and pathological injury of spleen were measured after a one-time total body irradiation of Co 7 rays (8 Gy). TUNEL staining was used to detect apoptosis of spleen cells. Enzyme-linked immunoassay ( ELISA) was applied to detect the contents of TNF-a, IL-1 p, IL-6, IL-18, NLRP3 and AIM2 in spleen. Western blot test and immunofluorescence staining test was employed to verify the changes of NLRP3 and AIM2 contents in spleen tissue after irradiation. Results DMF could obviously improve the survival rate of irradiated mice, improve the weight loss of irradiated mice, re-duce the pathological injury of spleen, and inhibit the apoptosis of spleen cells after irradiation. ELISA results showed that DMF could significantly inhibit the increase of spleen inflammatory cytokines TNF-a, IL-lp, IL-6, IL-18 and inflammasome components NL-RP3 and AIM2 induced by irradiation. Western blot and tissue immunofluorescence staining also confirmed that DMF could inhibit the increase of NLRP3 and AIM2 inflammasome protein levels caused by irradiation. Meanwhile, NLRP3 agonist and AIM2 agonist could antagonize the radiation protection effect of DMF on spleen cells. Conclusion DMF can ameliorate spleen injury of Co 7-ray injured mice, and its mechanism is closely related to NLRP3/AIM2 inflamma-somes, which can be used as a potential protective drug for radiation injury.

Effects of ionizing radiation on blood pressure and electrocardiography among healthcare workers in department of cardiovascular diseases / 中国辐射卫生

Objective To examine the effects of ionizing radiation on blood pressure and electrocardiography among healthcare workers in department of cardiovascular diseases, and to provide a reference for formulating the protective interventions against radiation exposure. Methods A total of 127 healthcare workers with radiation exposure in the Department of Cardiovascular Diseases of The 904th Hospital of the Joint Logistics Support Force of the PLA from 2018 to 2022 were included in the observation group. Meanwhile, 127 age- and gender-matched healthcare workers without radiation exposure in the same department during the same study period were included in the control group. The systolic blood pressure, diastolic blood pressure, heart rate, and the detection rates of hypertension and abnormal electrocardiography were compared between groups. Results There were no significant differences between groups in mean age (t = 0.77, P > 0.05), sex (χ2 = 0.02, P > 0.05), prevalence of smoking (χ2 = 0.28, P > 0.05), and alcohol consumption (χ2 = 0.02, P > 0.05). There were significant differences between the observation and control groups in systolic blood pressure [(127.77 ± 15.43) mmHg vs. (111.23 ± 19.10) mmHg; t = 4.21, P < 0.05], diastolic blood pressure [(79.32 ± 8.23) mmHg vs. (69.91 ± 10.21) mmHg; t = 4.09, P < 0.05], prevalence of hypertension [17.32% (22/127) vs. 8.66% (11/127); χ2 = 4.21, P < 0.05], heart rate [(81.10 ± 11.27) beats/min vs. (70.45 ± 10.55) beats/min; t = 4.33, P < 0.05], and abnormal rate of electrocardiography [21.26% (27/127) vs. 10.24% (13/127); χ2 = 5.82, P < 0.05]. Conclusion Ionizing radiation affects blood pressure and electrocardiography among healthcare workers in department of cardiovascular diseases. The prevention and monitoring of radiation exposure and occupational physical examination should be improved among healthcare workers with exposure to radiation in the department of cardiovascular diseases, with aims to reduce the hazard of radiation exposure and protect the health of healthcare workers.

Effects of fractionated low-dose ionizing radiation in the induction of EA.hy926 cell senescence / 中国辐射卫生

Objective To investigate the mechanism of fractionated low-dose ionizing radiation (LDIR) in the induction of EA.hy926 cell senescence. Methods EA.hy926 cells were irradiated with X-ray at 0, 50, 100, and 200 mGy × 4, respectively, and cultured for 24, 48, and 72 h. Several indicators were measured, including the levels of cellular senescence-associated β-galactosidase (SA-β-gal) staining, mRNA levels of senescence-associated cell cycle protein-dependent kinase inhibitor genes CDKN1A and CDKN2A, reactive oxygen species (ROS), total antioxidant capacity (T-AOC), and phosphorylated H2A histone family member X (γ-H2AX). Results After 4 fractionated LDIR, compared with the control group, the treatment groups showed increased nucleus area, blurred cell edge, and increased SA-β-gal positive area (P < 0.05) at 24, 48 and 72 h. After 4 fractionated LDIR, the mRNA level of CDKN1A increased in the 100 and 200 mGy × 4 groups at 24 and 48 h (P < 0.05), and CDKN2A mRNA level increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). The fluorescence intensity of ROS increased in treatment groups at 24, 48, and 72 h after 4 fractionated LDIR (P < 0.05). After 4 fractionated LDIR, the T-AOC level increased in the 100 and 200 mGy × 4 groups at 24 h (P < 0.05), and T-AOC level increased in all treatment groups at 48 and 72 h (P < 0.05). After 4 fractionated LDIR, γ-H2AX fluorescence intensity increased in all treatment groups at 24 h (P < 0.05), and the fluorescence intensity increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). Conclusion Fractionated LDIR can induce cellular senescence in EA.hy926 cells by impacting the cellular oxidation-antioxidation and oxidative damage levels, and the effects were relatively evident at 100 and 200 mGy.

Association between deacetylase Sirtuins and radiation-induced liver disease / 临床肝胆病杂志

Radiation-induced liver disease （RILD）， also known as radiation hepatitis， is subacute liver injury induced by radiation. As the focus of senescence-related studies， the deacetylase family Sirtuins （SIRTs） have the molecular functions including DNA repair and chromatin regulation， which makes SIRTs a hub for regulating genome and epigenome stability. Radiation-induced hepatic DNA damage and reaction is the primary physiological and pathological process of RILD， which is similar to the function of SIRTs. This article briefly introduces the structure and function of the SIRTs protein family， elaborates on the basic concepts and progress of the physical physiology of radiation therapy， discusses the internal relationship between SIRTs and RILD from the perspective of radiobiology， and points out the possibility of SIRTs as a target for the prevention and treatment of RILD.

El conocimiento y cumplimiento de las normas de protección sobre la radiación ionizante en una clínica dental docente

Introducción: El uso de radiografías como elemento complementario para el diagnóstico es fundamental para la práctica profesional de todo cirujano dentista. Por tanto, es importante conocer no solo los beneficios de la radiología oral y los fundamentos de protección radiológica, sino también determinar su nivel de aplicación o la adherencia frente al cumplimiento de los aspectos normativos que regulan el uso de la radiación ionizante en odontología. Objetivo: Relacionar el conocimiento sobre los cuidados en radiología bucal, las ventajas y los peligros en la toma de radiografías con el cumplimiento de las normas de protección radiológica y radiación ionizante en estudiantes de odontología de una clínica dental docente. Métodos: La población de estudio estuvo constituida por 180 estudiantes del cuarto año de la carrera de odontología, que emplearon los equipos radiológicos en la clínica docente asistencial durante los años 2019 (segundo semestre) y 2020 (primer trimestre). Se tomó como muestra representativa a 104 estudiantes, incorporados al estudio mediante muestreo aleatorio simple. Se aplicaron dos instrumentos de recolección de datos, uno para evaluar el conocimiento (cuestionario) y otro para verificar el cumplimiento de normas (lista de chequeo) sobre la protección radiológica y el diagnóstico por imágenes en la práctica odontológica. Para el análisis estadístico se aplicó la prueba estadística chi cuadrado con un nivel de significancia del 95 %. Resultados: No se encontró relación estadísticamente significativa (p = 0,30) entre el conocimiento teórico sobre la protección radiológica y el diagnóstico por imágenes, respecto el cumplimiento de las normas que regulan su aplicación (p > 0,05). El 90 % de participantes tienen conocimientos entre regulares y excelentes. Sin embargo, solo el 32 % cumple las normas técnicas de protección sobre radiación ionizante en su práctica clínica. Conclusión: Los estudiantes de odontología tienen suficiente conocimiento sobre protección radiológica y diagnóstico por imágenes. Sin embargo, este conocimiento no se refleja en prácticas adheridas a las normas.

Introduction: The use of radiographs as a complementary element for diagnosis is fundamental to the professional practice of every dental surgeon. Therefore, it is important to know not only the benefits of oral radiology and the fundamentals of radiological protection, but also to determine their level of application or adherence to compliance with the regulatory aspects that regulate the use of ionizing radiation in dentistry. Objective: To relate the knowledge of oral radiology care, the advantages and dangers in taking radiographs with compliance with the norms of radiological protection and ionizing radiation in dental students of a dental teaching clinic. Methods: The study population consisted of 180 fourth year dental students who used the radiological equipment in the teaching dental clinic during 2019 (second semester) and 2020 (first quarter). A representative sample of 104 students was taken, incorporated into the study by simple random sampling. Two data collection instruments were applied, one to evaluate knowledge (questionnaire) and the other to verify compliance with standards (checklist) on radiological protection and diagnostic imaging in dental practice. For the statistical analysis the chi-square statistical test was applied with a significance level of 95 %. Results: No statistically significant relationship was found (p = 0.30) between theoretical knowledge of radiological protection and diagnostic imaging with respect to compliance with the norms that regulate its application (p > 0.05). Ninety percent of participants have fair to excellent knowledge. However, only 32 % comply with the technical norms of ionizing radiation protection in their clinical practice. Conclusion: Dental students have sufficient knowledge of radiation protection and diagnostic imaging. However, this knowledge is not reflected in practices that adhere to the standards.

A radiation free alternative to CBCT volumetric rendering for soft tissue evaluation / Um método alternativo à TCFC sem radiação ionizante para a avaliação de tecidos moles da face

Objective: The aim of the present study is to evaluate whether a "radiation free" method using 3D facial scan can replace Cone Beam Computed Tomography (CBCT) volumetric rendering of soft tissue of the patient to assess maxillofacial surgery outcomes and compare the reference points and angular measurements of patient facial soft tissue. Material and Methods: Facial soft tissue scan of the patient's face, before and after orthognathic surgery and a CBCT of the skull for volumetric rendering of soft tissues were carried out. The 3D acquisitions were processed using Planmeca ProMax 3D ProFace® software (Planmeca USA, Inc.; Roselle, Illinois, USA). The participant were positioned in a natural position during the skull scannering. Three sagittal angular measurements were performed (Tr-NA, Tr-N-Pg, Ss-N-Pg) and two verticals (Go-N-Me, Tr-Or-Pg) on facial soft tissue scan and on the patient's 3D soft tissue CBCT volumetric rendering. Results: A certain correspondence has been demonstrated between the measurements obtained on the Proface and those on the CBCT. Conclusion: A radiation free method was to be considered an important diagnostic tool that works in conditions of not subjecting the patient to harmful ionizing radiation and it was therefore particularly suitable for growing subjects. The soft tissue analysis based on the realistic facial scan has shown sufficient reliability and reproducibility even if further studies are needed to confirm the research result.(AU)

Objetivo:Avaliar se um método "livre de radiação" usando escaneamento facial 3D pode substituir a renderização volumétrica da tomografia computadorizada de feixe cônico (TCFC) dos tecidos moles do paciente para analisar os resultados da cirurgia maxilofacial e comparar os pontos de referência e medições angulares afim de avaliar a correspondência entre as duas metodologias. Material e Métodos: Foi realizado o escaneamento dos tecidos moles faciais do paciente, antes e depois da cirurgia ortognática e uma tomografia computadorizada de feixe cônico do crânio para renderização volumétrica dos tecidos moles. As aquisições 3D foram processadas usando o software Planmeca ProMax 3D ProFace® (Planmeca USA, Inc.; Roselle, Illinois, USA). O participante foi posicionado em posição natural durante o escaneamento do crânio. Três medições angulares sagitais foram realizadas (Tr-NA, Tr-N-Pg, Ss-N-Pg) e duas verticais (Go-N-Me, Tr-Or-Pg) nas imagens de scaneamento e nas imagens do tecido mole facial da reconstrução tridimensional da TCFC. Resultados: Uma certa correspondência foi demonstrada entre as medidas obtidas no Proface® e aquelas na TCFC. Conclusão: Um método livre de radiação deve ser considerado uma importante ferramenta de diagnóstico que funciona em condições de não submeter o paciente a radiação ionizante nociva e, portanto, é particularmente adequado para indivíduos em crescimento. A análise de tecidos moles com base na varredura facial realista mostrou confiabilidade e reprodutibilidade, porém mais estudos são necessários para confirmar o resultado da pesquisa. (AU)

Analysis of occupational health examination results of radiation workers in Dezhou, China / 中国辐射卫生

Objective To investigate the occupational health status of radiation workers in Dezhou, China, explore the effects of low-dose ionizing radiation on the health of radiation workers, and provide a basis for improving the health of radiation workers. Methods A total of 1101 radiation workers in Dezhou who underwent occupational health examination in 2021 were selected. The effects of physical examination type, type of work, sex, length of service, and age on the health status of radiation workers were compared and analyzed. Results The abnormal rates of abdominal color Doppler ultrasound and eye lens were significantly higher in pre-post radiation workers than in radiation works (P < 0.05). The abnormal rates of eye lens increased with the length of service in radiation workers (P < 0.05). The abnormal rate of abdominal color Doppler ultrasound in male workers was higher than that in female workers, while the abnormal rates of blood routine and thyroid function were higher in female workers than in male workers (P < 0.05). Conclusion The abdominal rates of color Doppler ultrasound and eye lens are relatively high among radiation workers in Dezhou. It is necessary to improve the protection awareness and strengthen the level of radiation protection, so as to ensure the occupational health of radiation workers.

Influencing factors for thyroid function among radiation workers in Wuhan City / 预防医学

Objective@# To investigate the thyroid functions and influencing factors among radiation workers in Wuhan City, so as to provide insights into occupational health monitoring among radiation workers.@*Methods @#Radiation workers receiving physical examinations in Wuhan Prevention and Treatment Center for Occupational Diseases from January to October 2022 were enrolled, and participants' gender, age, smoking, alcohol consumption, medical history, medication use, types of occupational radiation and work duration were collected. Triiodothyronine (TT3), thyroxine (TT4), free thyroxine (FT4), free triiodothyronine (FT3) and thyroid stimulating hormone (TSH) were measured using a magnetic microparticle-based chemiluminescence immunoassay. Personnel dose equivalent was monitored using thermoluminescent dosimetry, and annual cumulative radiation dose was estimated. Factors affecting thyroid function were identified using a multivariable linear regression model.@*Results@#Totally 978 radiation workers were recruited, with a median age of 32.00 (interquartile range, 10.00) years, and including 782 men (79.96%) and 196 women (20.04%). There were 246 smokers (25.15%), 257 workers with alcohol consumption (26.28%) and 489 with a history of radiation work (50.00%). The median annual cumulative radiation dose was 0.20 (interquartile range, 0.24) mSv. The percentage of abnormal thyroid function was 14.72%. Multivariable logistic regression analysis showed that women (OR=1.925, 95%CI: 1.061-3.490), history of radiation work (OR=2.810, 95%CI: 1.119-7.057) and involving in medical application (OR=1.915, 95%CI: 1.101-3.332) were associated with abnormal thyroid function.@*Conclusions@#The percentage of abnormal thyroid function was 14.72% among radiation workers in Wuhan City. History of exposure to ionizing radiation, types of occupational radiation and gender were main factors affecting thyroid function.

Research progress of cell death in radiation protection and radiosensitization / 中国辐射卫生

@#The rapid advances in technology and medicine have greatly facilitated the application of ionizing radiation. Clinically, radiotherapy is one of the major treatments for malignant tumors. However, besides killing tumor cells, ionizing radiation inevitably leads to radiation damage and even death of normal cells. How ionizing radiation causes cell death and the forms of cell death have always been important research topics in this field. Recently, several forms of cell death induced by irradiation have been discovered. Apart from apoptosis, pyroptosis, necroptosis, ferroptosis, autophagic cell death, and methuosis have gradually become research hotspots, and provide new targets for the development of radioprotective drugs and radiosensitizers. In this review, we summarize various forms of ionizing radiation-induced cell death and related molecular mechanisms. We also introduce the latest progress in radiation protection and radiosensitization based on these cell death mechanisms. This review will provide a reference for the research and development of radioprotective drugs and radiosensitizers in the future.

Protective effects of WR-2721 combined with lentinan and cytokines against radiation damage / 中国辐射卫生

@#<b>Objective</b> To investigate the synergistic protective effects of WR-2721 combined with lentinan and cytokines against radiation damage in mice, and to provide a new treatment for acute radiation injury. <b>Methods</b> Seventy Institute of Cancer Research mice were divided into seven groups: a control group, a model group, WR-2721 group, Lentinan & cytokine group, WR-2721 & Lentinan group, WR-2721 & cytokine group and WR-2721 & Lentinan & cytokine group. All groups except the control group were irradiated with ⁶⁰Co γ-rays at a dose rate of 0.8 Gy/min and a cumulative dose of 5.0 Gy. The mice were sacrificed by cervical dislocation 14 d after irradiation to measure their spleen index, thymus index, and serum levels of superoxide dismutase (SOD), malondialdehyde (MDA), interleukin-11 (IL-11), and tumor necrosis factor-alpha (TNF-α). <b>Results</b> For the mice treated with WR-2721, lentinan, and cytokines, the spleen index was 7.33 ± 2.84, the thymus index was 1.70 ± 0.30, the serum SOD level was 114.0 ± 8.3, the MDA level was 7.33 ± 1.16, the IL-11 level was 155.8 ± 49.4, and the TNF-α level was 174.0 ± 37.8. All these indicators except the spleen index in the combination group significantly differed from those of the model group (<i>P</i> < 0.05 or 0.01), indicating the combined treatment promoted recovery from radiation damage. <b>Conclusion</b> WR-2721 combined with lentinan and cytokines has significant synergistic protective effects, which is a promising treatment for acute radiation injury.

Effects of low-dose radiation on oxidative stress and damage repair in HBE cells / 中国辐射卫生

@#<b>Objective</b> To investigate the effects of lowdose ionizing radiation (LDIR) on oxidative stress and damage repair in human bronchial epithelial (HBE) cells. <b>Methods</b> HBE cells were divided into 0, 50, 100, and 200 mGy groups, and cultured for 24 and 48 h after X-ray irradiation, respectively. The cell viability, levels of glutathione (GSH), malondialdehyde (MDA), and 8-hydroxy-2’-deoxyguanosine (8-OHdG), and transcriptional levels of DNA damage repair genes <i>PPP2R2D</i> and <i>TP53</i> were measured. <b>Results</b> At 24 h after irradiation, there was no significant difference in the cell viability between the dose groups and the control group (<i>P</i> > 0.05); all dose groups had significantly increased MDA level, dose-dependently decreased GSH level, dose-dependently increased 8-OHdG level, and significantly increased mRNA level of <i>PPP2R2D</i> gene (all <i>P</i> < 0.05); the mRNA expression level of <i>TP53</i> gene was significantly increased in the 50 mGy group (<i>P</i> < 0.05). At 48 h after irradiation, there were the highest cell viability, significantly decreased MDA and 8-OHdG levels, and significantly increased mRNA expression levels of <i>PPP2R2D</i> and <i>TP53</i> genes in the 50 mGy group compared with the control group (all <i>P</i> < 0.05); the GSH level in the 100 mGy group was significantly increased (<i>P</i> < 0.05). <b>Conclusion</b> LDIR, especially radiation at 50 mGy, can affect the oxidative-antioxidant level in HBE cells and the transcript-level differential expression of DNA damage repair genes.

Research progress of irradiation injuries anti-agents / 中华劳动卫生职业病杂志

Irradiation injuries anti-agents refer to drugs that can inhibit the initial stage of radiation injuries, or reduce the development of radiation injuries and promote the recovery of injuries when used early after irradiation exposure. According to the mechanism of action and the time of intervention, the irradiation injuries anti-agents are divided into four categories: radioprotectors, radiomitigators, radiation therapeutics for external radiation exposure, and anti-agents for internalized radionuclides. In this paper, the research progress of irradiation injuries anti-agents in recent years is reviewed.

Effect and mechanism of ionizing radiation on ferroptosis in mouse hepatocytes / 中华放射肿瘤学杂志

Objective:To investigate the effect and mechanism of ionizing radiation on ferroptosis in mouse hepatocytes.Methods:Twenty-four C57BL/6J mice were divided into two groups by random number table method: healthy control group (control group, n=6) and irradiation group (whole liver was irradiated with a single dose of 30 Gy X-ray, n=18). Mice were sacrificed at 6, 24 and 72 h (6 mice per time point) after irradiation to obtain liver tissue and plasma samples. The contents of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in plasma were measured by automatic biochemical analyzer. The prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured by automatic biochemical analyzer. Pathological changes of liver tissues were observed by hematoxylin-eosin (HE) staining. The iron deposition in liver tissues was detected by Prussian blue staining. The expression levels of 4-Hydroxynonenal (4HNE) and hepcidin in the liver were determined by immunohistochemical staining, and quantitative analysis was performed. Plasma malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, total antioxidant capacity (T-AOC) and glutathione (GSH) content were determined by microplate reader analysis according to the kit instructions. The expression levels of transferrin receptor 1 (TfR1), p53, solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) in the liver were measured by Western blot. Results:Compared with the control group, the plasma contents of ALT ( t=5.15, 5.47, both P<0.001) , AST at 6 and 24 h after irradiation were increased ( t=8.42, 2.50, both P<0.001), the plasma PT was prolonged ( t=3.12, P=0.011) and the APTT was shortened ( t=3.26, P=0.009) at 72 h after radiation in the irradiation group. Histopathological results showed that evident liver edema was observed at 6, 24 and 72 h after irradiation ( t=9.58, 10.09, 18.70, all P<0.001). Different degrees of iron deposition were observed ( t=8.57, 15.31, 32.11, all P<0.001). The infiltration of hepcidin positive cells was significantly increased after irradiation ( t=5.36, 13.17, 17.11, all P<0.001). The number of 4HNE positive cells was significantly increased ( t=18.86, 22.67, 9.12, all P<0.001). At the same time, ionizing radiation induced a significant increase in plasma MDA content ( t=4.36, 7.47, 8.22, all P<0.001), and a decrease in SOD ( t=4.52, 5.80, 7.60, all P<0.001), T-AOC ( t=13.24, 20.49, 24.96, all P<0.001) and GSH ( t=2.78, 6.07, 11.25, P=0.020, <0.001, <0.001), respectively. The expression level of TfR1 protein was significantly up-regulated ( t=3.46, 5.40, P=0.026, 0.006), whereas that of GPX4 protein was significantly down-regulated ( t=11.88, 30.63, both P<0.001) at 24 and 72 h after irradiation. At 6, 24 and 72 h after irradiation, the expression level of p53 protein was significantly up-regulated and maintained at a high level ( t=7.84, 4.25, 8.22, P=0.001, 0.013, 0.001), while that of SLC7A11 protein was significantly down-regulated ( t=9.29, 19.96, 9.09, all P<0.001). Conclusion:Ionizing radiation induces the ferroptosis in hepatocytes, and its mechanism may be related to the activation of p53-SLC7A11-GPX4 pathway.

Meta-analysis of the effects of low-dose ionizing radiation on the thyroid of medical radiation workers / 中华放射医学与防护杂志

Objective:To assess the effects of low-dose ionizing radiation on the thyroid of medical radiation workers.Methods:Based on the inclusion and exclusion criteria, 27 articles, involving 22 937 individuals, were screened finally from relevant literature published from 1996 to 2022. Meta-analysis was carried out using Stata 16.0 for serum levels of triiodothyronine (T 3), free triiodothyronine (FT 3), thyroid hormone (T 4), free thyroid hormone (FT 4), thyrotropin-stimulating hormone (TSH) and thyroid nodule rates. As well, subgroup analysis were carried out of thyroid function in different types of radiation workers. Results:The standardized mean difference (SMD) at T 3 and T 4 levels for radiation workers was -0.19 (-0.37, -0.01) and -0.34 (-0.38, -0.30), lower than that of control group ( Z=2.07, -16.06, P<0.05). The SMD at FT 4 levels for radiation workers was 0.22 (0.06, 0.39), higher than control group ( Z=2.61, P<0.05). The relative risk of thyroid nodules in radiation workers was 1.47 (1.19, 1.82), higher than that of control group ( Z=-3.58, P<0.05). The analysis result for subgroup showed that the SMD for T 3, T 4 and TSH levels in the interventional radiology workers were -0.29 (-0.51, -0.07), -0.31 (-0.47, -0.15) and -0.43 (-0.73, -0.13) ( Z=-2.55, -3.86, -2.82, P<0.05), respectively, and the SMD for T 4 levels in the nuclear medicine workers was -0.26 (-0.45, -0.07), which meaned a reduced risk compared to the control group ( Z=-2.70, P<0.05). Conclusions:Long-term low doses of ionising radiation may have adverse effects on thyroid hormone and thyroid nodule in radiation workers, particularly in interventional radiology workers, and attention should be focused on their radiation protection.

Mechanisms of copper transporter 1 gene in regulating radiation induced intestinal injury / 中华放射医学与防护杂志

Objective:To investigate the effects and mechanisms of copper transporter 1 (CTR1) in radiation induced intestinal injury in vitro. Methods:Human small intestinal epithelial cells (HIEC) were irradiated with 2, 4, 6, 8 Gy of X-rays and rat intestinal epithelial cells (IEC-6) were irradiated with 5, 10, 15, 20 Gy of X-rays. At 2, 4, 8, 24, and 48 h after irradiation, the expression of CTR1 was detected by Western blot assay. In some experiments, HIEC and IEC-6 cells were transfected with CTR1 shRNA and then exposed to X-rays. Copper levels were detected by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The radiosensitivity of cells was verified by colonogenic assay, the cellular reactive oxygen species (ROS) level and DNA damage were detected to further explore the related mechanism. In addition, Western blot was applied to detect the expressions of antioxidants and cuproptosis associated proteins in enterocytes after silencing CTR1 or irradiation.Results:The expression of CTR1 was increased by X-ray irradiation in a dose-dependent manner ( t=3.53, 3.45, 6.37, 11.11, 11.13, P<0.05). CTR1 expression was successfully diminished by CTR1 shRNA adenovirus vectors. According to the survival curves, the enhancement ratios of the radiosensitivity of HIEC and IEC-6 cells with CTR1 knocking-down were 1.146 and 1.201, respectively. Radiation-induced copper accumulation was alleviated after CTR1 silencing in IEC-6 cells ( t=3.10, P<0.05). At 0.5 h after irradiation, the ROS production in the CTR1 knockdown group was significantly lower than that in the control group ( t=5.23, 2.96, P<0.05). At 1 h after irradiation, the protein expression of γ-H2AX in the CTR1 knockdown group was obviously lower than that in the control group ( t=7.50, 4.29, P<0.05). The expressions of Nrf2 and HO-1 were increased after irradiation, which could be further increased after CTR1 silencing. In addition, cuproptosis associated protein DLAT, LIAS and FDX1 were reduced post-irradiation, which were recovered after CTR1 silencing. Conclusions:The radioresistance of HIEC and IEC-6 cells was enhanced after CTR1 silencing, possibly through the intracellular ROS and cuproptosis pathway.

Effect of circular RNA hsa_circZDHHC21_004 on the proliferation of the human small intestinal epithelial cells HIEC-6 exposed to 60Co γ-rays / 中华放射医学与防护杂志

Objective:To study the influence of circular RNA hsa_circZDHHC21_004 on the proliferation of human small intestinal epithelial cells HIEC-6 after 60Co γ-rays exposure. Methods:HIEC-6 cells were exposed to 60Co γ-rays at 0, 5, 10, and 15 Gy with a dose rate of 1 Gy/min. The expression level of hsa_circZDHHC21_004 in the irradiated HIEC-6 cell was detected. Hsa_circZDHHC21_004 was knocked-down to investigate the influences of hsa_circZDHHC21_004 on the proliferation of irradiated HIEC-6 cells by CCK-8 assay and colony formation assay. Results:The expression level of hsa_circZDHHC21_004 in HIEC-6 cells was upregulated by (1.00±0.24), (1.34±0.28), (1.85±0.31), and (2.80±0.64) times of control after 0, 5, 10, and 15 Gy irradiation, respectively and there were significant difference between 10 or 15 Gy group and 0 Gy group ( F=10.86, P=0.008). Knockdown of hsa_circZDHHC21_004 significantly increased the proliferation rate of HIEC-6 cells at 24, 48, and 72 h after 10 Gy irradiation compared with non-irradiated control ( t=-6.25, -5.83, -7.75, P < 0.001). Under 2 and 5 Gy irradiation, the clone formation rates of the hsa_circZDHHC21_004 knockdown cells were significantly higher than those of the control ( t=-7.45, -8.83, P<0.01). Conclusions:Hsa_circZDHHC21_004 is increased after irradiation and influenced the proliferation of irradiated HIEC-6 cells.

Research progress of the roles of metabolic reprogramming in radiation-induced direct- and bystander-effects / 中华放射医学与防护杂志

Metabolic reprogramming refers to the phenomenon that tumor cells, in order to meet their own growth and energy needs, regulate their biological functions by changing their metabolic mode, help themselves resist external stresses, and thus enable cells to adapt to hypoxia, acid, nutrient deficiency and other microenvironments and rapidly proliferate. It was found that metabolic reprogramming could contribute to radiation resistance and it also could be induced in bystander cells which may result in radiation resistance and the cancellation. Investigation the mechanism of radiation-induced metabolic reprogramming may provide new ideas and a theoretical framework for radiation protection, radiotherapy, and radio-diagnosis. This article reviewed the research progress on the mechanism of metabolic reprogramming in the direct and bystander effects of radiation.

Research progress on the role and mechanism of premature cellular senescence on wound healing in radiation-induced skin injury / 中华放射医学与防护杂志

Radiation skin injury can be induced by medical exposure, occupational exposure, and emergency exposure. Many relevant studies focused on the prevention and treatment of radiation-induced skin injury, but the underlying molecular mechanisms have not been fully clarified. It has been demonstrated that radiation-induced premature cellular senescence is involved in radiation skin injury. To discuss the relationship between radiation-induced premature cellular senescence and radiation-induced skin injury, this paper reviewed the mechanism of radiation-induced skin injury, the promotion of premature cellular senescence and related signal pathways, and the role of premature cellular senescence in wound healing.