Studies on the role of moderate doses of ionizing radiation-induced cellular senescence in mouse lung tissue.

PURPOSE: To investigate the role of moderate doses of ionizing radiation-induced cellular senescence in mouse lung tissue and whole-body inflammation levels. MATERIAL AND METHODS: Forty-two C57BL/6J mice were randomly divided into the control group, the 1, 3, and 7 days after 2 Gy irradiation group, and the 1, 3, and 7 days after 4 Gy irradiation group, with six mice in each group. The histopathology, cellular senescence, oxidative-antioxidant, DNA damage repair, and inflammation-related indicators of irradiated mice were examined. RESULTS: Compared with the control group, the histopathological scores, the positive area of senescence-associated-ß-galactosidase (SA-ß-Gal) staining, and the mRNA levels of senescence-related genes in the lung tissues in all dose groups increased on 1, 3, and 7 days after irradiation. In peripheral blood, erythrocytes, leukocytes, platelets, hemoglobin, 8-hydroxydeoxyguanosine (8-OHdG), C-reactive protein, and other indicators showed a different trend in all dose groups. The levels of malondialdehyde(MDA), superoxide dismutase (SOD), glutathione (GSH), and 8-OHdG in the lung tissue showed different trends after 2 Gy and 4 Gy irradiation. The 8-Oxoguanine DNA glycosylase 1 (hOGG1) and O-6-methylguanine-DNA methyltransferase (MGMT) mRNA levels showed a trend of increasing and then decreasing. The levels of whole-body inflammation were significantly correlated with the levels of indicators related to cellular senescence and damage repair in the lung tissue of mice. CONCLUSIONS: The moderate doses of ionizing radiation induce oxidative stress, and DNA damage and increase DNA repair gene expression in mouse lung tissue. The lung tissue cellular senescence correlates with the level of whole-body inflammation.

Correlation analysis of occupational stress and metabolic syndrome among employees of a power grid enterprise in China.

BACKGROUND: Being in a state of high occupational stress may disrupt the metabolic balance of the body, thus increasing the risk of metabolic diseases. However, the evidence about the relationship between occupational stress and metabolic syndrome was limited. OBJECTIVES: To explore the association between occupational stress and metabolic syndrome (MetS) in employees of a power grid enterprise. METHODS: A total of 1091 employees were recruited from a power grid enterprise in China. Excluding those who failed to complete the questionnaire and those who had incomplete health check-ups, 945 subjects were included in the study. Assessment of occupational stress was used by job demand-control (JDC) and effort-reward imbalance (ERI) questionnaires, respectively. The information on body mass index (BMI), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were collected. The levels of high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and fasting blood glucose (FBG) in the fasting venous blood samples were measured. Logistic regression analysis and multiple linear regression methods were used to analyze the correlation between JDC and ERI models of occupational stress, metabolic syndrome, and its components, respectively. RESULTS: The prevalence of MetS was 8.4% and 9.9% in JDC and ERI model high occupational stress employees, respectively. ERI model occupational stress and smoking are significantly associated with the risk of MetS. ERI ratio was significantly associated with lower HDL-C levels. Gender, age, marital status, smoking, high-temperature and high-altitude work were significantly associated with metabolic component levels. CONCLUSION: Our study revealed a high detection rate of occupational stress in both JDC and ERI models among employees of a power grid enterprise. ERI model occupational stress, demanding more attention, was associated with the risk of MetS as well as its components such as HDL-C.

Correlation analysis between occupational stress and metabolic syndrome in workers of a petrochemical enterprise: based on two assessment models of occupational stress.

BACKGROUND: Occupational stress is becoming a common phenomenon around the world. Being in a high occupational stress state for a long time may destroy the metabolic balance of the body, thereby increasing the risk of metabolic diseases. There is limited evidence regarding the correlation between occupational stress and metabolic syndrome (MetS), particularly in the petrochemical workers. METHODS: A total of 1683 workers of a petrochemical enterprise in China were included in the survey by cluster sampling method. The occupational stress assessment was carried out by the Job Content Questionnaire and the Effort-Reward Imbalance Questionnaire, and the general demographic characteristics, work characteristics, occupational hazards, lifestyle and health examination data of the participants were collected. Logistic regression and multiple linear regression were used to analyze the correlations and influencing factors between occupational stress and its dimensions with MetS and its components. RESULTS: A total of 1683 questionnaires were sent out, and 1608 were effectively collected, with an effective recovery rate of 95.54%. The detection rates of occupational stress in Job Demand-Control (JDC) and Effort-Reward Imbalance (ERI) models were 28.4% and 27.2%, respectively. In this study, 257 participants (16.0%) were diagnosed with MetS. Compared with the non-MetS group, body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglycerides (TG) and fasting blood-glucose (FBG) levels were significantly higher in the MetS group, and high density lipoprotein-cholesterol (HDL-C) levels were significantly lower (P < 0.001). The results of multiple linear regression showed that after adjusting for nation, marital status, education, work system, smoking and drinking, and further adjusting for occupational hazards, the D/C ratio was significantly negatively correlated with SBP in the JDC model. Social support was negatively correlated with WC. In the ERI model, there was a significant positive correlation between over-commitment and FBG. CONCLUSIONS: The detection rates of occupational stress and MetS were high in workers of a petrochemical enterprise. In the JDC model, occupational stress was negatively correlated with SBP, and social support was negatively correlated with WC. In the ERI model, there was a significantly positive correlation between over-commitment and FBG.

Functional analysis of polymorphism haplotypes of MGMT in residents of high background radiation area.

To investigate the distribution of polymorphisms and their frequent haplotypes in the regulatory region of MGMT in residents of high background radiation area (HBRA) and their impacts on transcriptional activity, we collected DNA samples from 83 healthy Chinese residents in HBRA and searched for genetic polymorphisms in the regulatory region of MGMT. Haplotypes were characterized by Haploview analysis. Transcriptional activities of different polymorphism haplotypes were detected by using a dual-luciferase reporter assay. Six genetic polymorphisms were identified within the regulatory region (1024 bp) of MGMT. Linkage disequilibrium (LD) patterns and haplotype profiles were analyzed using the identified genetic polymorphisms. These polymorphisms we found to be in high LD, with a D' of 0.928 (r2 = 0.581) for -808 T>C and -19 C>T, 0.928 (r2 = 0.581) for -797 G>A and -19 C>T in Han Chinese HBRA residents. Complete LD with a D' of 1.0 (r2 = 1.0) was observed between -808 T>C and -797 G>A. Haploview analysis revealed the existence of three polymorphism haplotypes in the core region of regulatory region of MGMT. Using serially truncated regulatory region of human MGMT luciferase reporter gene constructs, we found a 1002 bp (-637 nt to +365 nt) fragment in the MGMT gene was the core region. Dual-luciferase reporter assays showed that different polymorphism haplotypes bearing different variant alleles exhibit distinct transcriptional activities, especially the polymorphism haplotype carrying -19 T has the strongest transcriptional activity. In summary, the present study obtained genetic characteristics of the six polymorphisms in the regulatory region of the MGMT gene in HBRA residents, and the results suggest that different polymorphism haplotypes have significant effects on the transcriptional activity of the MGMT and that the -19 C>T polymorphism may be a functional variant involved in the transcriptional regulation of the MGMT gene.

Analysis of occupational stress and its correlation with oxidative-antioxidant levels among employees of a power grid enterprise in Guangdong.

BACKGROUND: Occupational stress and its health effects on occupational populations have attracted extensive attention from researchers in public health. The stressors faced by employees of power grid enterprises are increasing progressively, which is easy to cause occupational stress. The balance of the body's oxidative-antioxidant levels plays an essential role in maintaining the body's health status. This study aims to explore occupational stress and its correlation with oxidative-antioxidant levels in employees of a power grid enterprise. METHODS: A cluster random sampling method was used to investigate the basic information of 528 employees in a power grid enterprise and investigate the two occupational stress models of employees by using the Job Content Questionnaire based on the job demand-control-support (JDC) model, and the Effort-Reward Imbalance Questionnaire based on the effort-reward imbalance (ERI) model, respectively. Peripheral blood samples were collected from the employees to measure the levels of malondialdehyde (MDA), total antioxidant capacity (TAC), and superoxide dismutase (SOD). The correlation between different models of occupational stress level and the body's oxidation-antioxidation level was further explored. RESULTS: The detection rate of high JDC model occupational stress was 50.6% and the detection rate of high ERI model occupational stress was 50.9%. The JDC model occupational stress was significantly associated with high-temperature and high-altitude operation, visual display terminal operation, monthly income, and exercise (all P < 0.05). The ERI model occupational stress was significantly associated with visual display terminal operation (all P < 0.05). The results of the generalized additive model showed that SOD levels had a non-linear relationship with the D/C ratio as well as the E/R ratio. With the D/C ratio close to 1, SOD levels raised rapidly. When the E/R ratio exceeded 1, the SOD level raised rapidly (all P<0.05) . TAC levels were negatively associated with the E/R ratio (P < 0.05). CONCLUSION: The detection rates of occupational stress in both models among employees in a power grid enterprise are higher. ERI model occupational stress was associated with body TAC and SOD levels, and JDC model occupational stress was associated with body SOD levels.