Study Of Short-Term Exposure Of Ambient Fine Particulate Matter And Its Association With Oxidative Stress Level

Objective:It has been implicated that oxidative stress as a primary pathogenic mechanism of PM_2.5induced adverse health effects.In recent years,several epidemiological studies have been using the derivatives of reactive oxygen metabolites（d-ROMs）to reflect the oxidative status of diseases or lifestyle-related diseases.However,there were few reports about the potential association between air pollutant exposure and d-ROMs at present.Meanwhile,as a complex mixture,different chemical components or sources of PM_2.5may have different effects.Oxidative potential was selected as the indicator to characterize associated PM_2.5compositions and sources most responsible for adverse impacts on human health.The aim of this study was to explore the association between the mass concentration and oxidation potential of PM_2.5and d-ROMs,a marker of oxidative stress in human serum.Methods:The research adopted the method of fixed group repeated measurement.Since December 2021 to August 2022,we recruited 30 adult college students in Guangzhou,Guangdong Province.We used individual portable air samples to collect PM_2.5samples during visits in winter and summer.And collected the finger blood of the subjects,centrifuge and take the supernate for d-ROMs test,and conducted the questionnaire survey.We used dithiothreitol assay to determine the oxidative potential level of PM_2.5.We used the linear mixed effect models to analyze the association between PM_2.5mass concentration and oxidation potential with different lag time and the oxidative stress marker d-ROMs in serum.Results:The average level of d-ROMs in serum was 333.71 U.CARR.The variance analysis of repeated measurement analysis showed that there were difference in the level of d-ROMs between men and women（P<0.05）,that women were higher than men.And there were no significant difference in the level of d-ROMs between winter and summer.During the study period,the average daily concentration of PM_2.5with different lag time were 36.34-41.22μg/m³.In healthy college students,serum d-ROMs were measured as biomarker of systemic oxidative stress and we found that short-term increases in PM_2.5were associated with increases in oxidative stress.The effect was strongest in lag 0 day.A 10μg/m³increase in PM_2.5was associated with increments of 3.36%（95%CI:1.23%,5.54%,,P<0.01）in serum d-ROMs on the current day.By analyzed winter and summer respectively,it was found that PM_2.5begins to had a positive impact on it at lag0,and had the greatest impact at lag0,and then shows a downward trend with the increase of lag time.Compared with the single pollutant model,the double pollutant model shows that the effect of PM_2.5mass concentration on d-ROMs is slightly enhanced.Under gender stratification,there was still a positive correlation between PM_2.5and d-ROMs level in women,but no significant correlation was found in men.Under exercise frequency stratification,there were a positive correlation between PM_2.5and d-ROMs level when the exercise frequency were 0-1 time/week and 2-4 times/week,and its effect has little change compared with the general population.The PM_2.5mass concentration has a negative correlation with OP^DTTm,but a positive correlation with OP^DTTv.The analysis of OP^DTTvby quartile showed that the serum d-ROMs level in the fourth quartile array increased by 4.99%（95%CI:0.04%,10.19%,P<0.05）compared with that in the first quartile array.However,no significant correlation were found between OP^DTTmand serum d-ROMs.Then,analyzed winter and summer respectively.In winter,the analysis of OP^DTTmby quartile showed that the serum d-ROMs level in the third quartile array increased by 7.98%（95%CI:0.33%,16.21%,P=0.04）compared with that in the first quartile array.The analysis of OP^DTTvby quartile showed that the serum d-ROMs level in the third quartile array increased by8.45%（95%CI:1.18%,16.24%,P=0.02）compared with that in the first quartile array in winter.The analysis of OP^DTTvby quartile showed that the serum d-ROMs level in the fourth quartile array increased by 9.59%（95%CI:3.38%,16.18%,P=0.003）compared with that in the first quartile array in summer.However,no significant correlation were found between OP^DTTmand serum d-ROMs in summer.Under gender stratification,no significant correlation were found between OP^DTTm,OP^DTTvand serum d-ROMs.Conclusions:1.Short-term exposure to PM_2.5can cause the increase of oxidative stress marker d-ROMs in healthy college students in Guangzhou,with immediate and delayed effects.2.The PM_2.5mass concentration has a negative correlation with OP^DTTm,but a positive correlation with OP^DTTv.3.OP^DTTvalso be a health index to reflect the oxidative stress effect of PM_2.5exposed.