Impact Of Fine Particles On Lung Cancer Mortality In Hebei Province And Lung Carcinogenesis In BALB/c Mice

Part one Impact of PM_2.5on lung cancer mortality in Hebei ProvinceObjective: The purpose of this study was to analyze the relationship between PM_2.5and lung cancer mortality in Hebei province,to estimate the number of lung cancer deaths attributed to PM2.5.This study may provide quantitative basis for the long-term health impact of air quality supervision in Hebei Province.Methods: In this study,we collected and described the average annual concentration of PM_2.5from 2001 to 2014 and lung cancer mortality rate from 2010 to 2014 in Hebei Province.Then using the generalized additive models and R software,we quantified the associations between lung cancer mortality and 10-years PM_2.5in Hebei Province of China.We also estimated lung cancer mortality burden attributable to PM_2.5in 2014.Result: 1.From 2001 to 2014,the average annual PM_2.5concentration in Hebei Province showed an upward trend,which was greater than the National Environmental Quality Grade II standard.In some areas,PM_2.5was greater than 100?g/m³.The spatial distribution of PM_2.5concentration in Hebei Province showed a decreasing trend from south to north.2.In 2010-2014,the mortality rate of lung cancer in Hebei provincial cancer registry showed an upward trend.In 2014,the mortality rate of lung cancer in Hebei provincial cancer registry was 41.43/105.The mortality rate was 54.87/105 for male and was 27.52/105 for female.3.We found that the 10-years PM2.5-lung cancer mortality associations were non-linear,with thresholds of 630?g/m³?63?g/m³?overall,690?g/m³?69?g/m³?for male,680?g/m³?68?g/m³?for female,660?g/m³?66?g/m³?for those aged 30-64 years,620?g/m³?62?g/m³?for those aged 65 years and more,above which the relative risks were 1.09?95%CI: 1.08,1.10?,1.06?95%CI: 1.03,1.10?,1.20?95%CI: 1.10,1.26?,1.07?95%CI: 1.05,1.11?,and 1.10?95%CI: 1.07,1.13?respectively.8.3%?95% CI: 7.4-9.1%?of lung cancer deaths can be attributed to PM_2.5in Hebei Province.About 5.7%?95%CI: 2.8-9.4%?of men and 9.9%?95%CI: 8.3-21.6%?for women were attributed to PM2.5.6.5%?95% CI: 4.7-10.3%?for those aged 30-64 years and 9.1%?95%CI: 6.4-11.5%?for those aged 65 years or more were attributed to PM2.5.Part Two Effect of PM_2.5on Lung Carcinogenesis in BALB/c MiceObjective: To explore the effect of PM_2.5on lung carcinogenesis in BALB/c mice.Methods: Real-time PM_2.5collector and systemic exposure system were used for PM_2.5collection and simulation of daily exposure environment.Based on the establishment of a lung cancer BALB/c mice model,BALB/c mice were exposed for 5 hours/day and exposed for 4 months.Each of the 7 mice in the test group and the control group was sacrificed at the 10 th and the 15 th week respectively.Then they were set up to observe the lung tissues.We analyzed the general structure,HE staining of lung tissues and the rate of carcinogenesis.Flow cytometry was used to detect T cell immune function,lung cell apoptosis,cell cycle in BALC/c mice.Result: After ten weeks,the rate of carcinogenesis of the test group and the control group were 57.14% and 16.67%,respectively,and the difference was not statistically significant?P>0.05?.After the fifteen week,there was a statistically significant difference about the rate of carcinogenesis between the experimental group?100%?and the controls?28.57%??P?0.05?.In the experimental group,the lung tissues were dark,with bulging and white spots on multiple spots,and irregular white bulges on the edges.The results of HE staining showed that most of the lung cells in the experimental group became cancerous.The ratio of CD4 positive cells and CD4/CD8 of the experimental group was significantly lower than that of the control group?P?0.05?.The apoptosis rate of lung tissue in the experimental group was significantly lower than that in the control group?P?0.05?.Conclusion: The lung cancer mortality was related to the 10-years cumulative exposure to PM_2.5in Hebei Province.Below the threshold,PM_2.5has almost no effect on lung cancer mortality.Above the threshold,lung cancer mortality increased with the increase of PM_2.5concentration.Animal experiments showed that long-term exposure to PM_2.5may reduce the immune response in lung cancer mice.It is suggested that PM_2.5may promote the occurrence of lung cancer in mice.