Multiple exposures to low-dose ionizing radiation induced the initiation and progression of pro-atherosclerotic phenotypes in mice and vascular endothelial cell damage.

OBJECTIVE: This study aimed to investigate the effects of low-dose radiation on the abdominal aorta of mice and vascular endothelial cells. METHODS: Wild-type and tumor-bearing mice were exposed to 15 sessions of low-dose irradiation, resulting in cumulative radiation doses of 187.5, 375, and 750 mGy. The effect on the cardiovascular system was assessed. Immunohistochemistry analyzed protein expressions of PAPP-A, CD62, P65, and COX-2 in the abdominal aorta. Microarray technology, Gene Ontology analysis, and pathway enrichment analysis evaluated gene expression changes in endothelial cells exposed to 375 mGy X-ray. Cell viability was assessed using the Cell Counting Kit 8 assay. Immunofluorescence staining measured γ-H2AX levels, and real-time polymerase chain reaction quantified mRNA levels of interleukin-6 (IL-6), ICAM-1, and Cx43. RESULTS: Hematoxylin and eosin staining revealed thickening of the inner membranes and irregular arrangement of smooth muscle cells in the media membrane at 375 and 750 mGy. Inflammation was observed in the inner membranes at 750 mGy, with a clear inflammatory response in the hearts of tumor-bearing mice. Immunohistochemistry indicated increased levels of PAPP-A, P65, and COX-2 post-irradiation. Microarray analysis showed 425 up-regulated and 235 down-regulated genes, associated with processes like endothelial cell-cell adhesion, IL-6, and NF-κB signaling. Cell Counting Kit 8 assay results indicated inhibited viability at 750 mGy in EA.hy926 cells. Immunofluorescence staining demonstrated a dose-dependent increase in γ-H2AX foci. Reverse transcription quantitative PCR results showed increased expression of IL6, ICAM-1, and Cx43 in EA.hy926 cells post 750 mGy X-ray exposure. CONCLUSION: Repeated low-dose ionizing radiation exposures triggered the development of pro-atherosclerotic phenotypes in mice and damage to vascular endothelial cells.

[Simulating the Fate of Typical Organochlorine Pesticides in the Multimedia Environment of the Pearl River Delta].

A level Ⅳ multimedia fugacity model was established to simulate the fate of p,p'-DDT and γ-HCH in special climatic conditions, such as in the high temperature and humidity environment of the Pearl River Delta, China. The law of migration and transformation of p,p'-DDT and γ-HCH were approached by the Ⅳ multimedia fugacity model, corrected for time and temperature change during 1952-2030. The simulation results showed a better response of the variation of pollutant concentrations to the changes in the pesticide application policy; the concentrations of these two targets in air, water, soil, and sediment were found continuing to increase with the growth of application rates, and decreased with the prohibition in the use of pesticide. We predicted that concentrations will decrease to 6.1×10-12, 3.2×10-9, 6.07×10-7, and 8.72×10-7 mol·m-3 for p,p'-DDT, and to 3.37×10-11, 1.14×10-8, 1.21×10-6, and 4.18×10-7 mol·m-3 for γ-HCH, in air, water, soil, and sediment, respectively, by 2030. The output values of the Ⅳ multimedia fugacity model corrected by designating temperature as a variable parameter, was closer to the survey results than the simulation results obtained by using the model with a constant temperature parameter. The results also showed the pattern of organochlorine pesticides transformation in the whole environmental media in the study area as follow:the pollutants transferred from air to soil, air to water, soil to water, and from water to sediment, and were lastly stored in the soil and sediment. The results of sensitivity analysis indicated that the emission rate, degradation rate, temperature, and lgKow had significant influences on the concentrations of p,p'-DDT and γ-HCH in all the above-mentioned environmental medias. Uncertainty analysis showed that changes in the whole parameter sets had great impact on air concentrations. There were seasonal variations in the distribution of organochlorine pesticide concentrations, and temperature change had influence on its partition in the environment.