Madden Michael C, Stevens Tina, Case Martin, Schmitt Michael, Diaz-Sanchez David, Bassett Maryann, Montilla Tracey S, Berntsen Jon, Devlin Robert B
EPHD, NHEERL, US EPA, Research Triangle Park, Chapel Hill, NC, 27711, USA.
U.S EPA Human Studies Facility, 104 Mason Farm Road, Chapel Hill, NC, 27599-7315, USA.
Part Fibre Toxicol. 2014 Sep 2;11:37. doi: 10.1186/s12989-014-0037-5.
The potential effects of combinations of dilute whole diesel exhaust (DE) and ozone (O₃), each a common component of ambient airborne pollutant mixtures, on lung function were examined. Healthy young human volunteers were exposed for 2 hr to pollutants while exercising (~50 L/min) intermittently on two consecutive days. Day 1 exposures were either to filtered air, DE (300 μg/m³), O₃ (0.300 ppm), or the combination of both pollutants. On Day 2 all exposures were to O₃ (0.300 ppm), and Day 3 served as a followup observation day. Lung function was assessed by spirometry just prior to, immediately after, and up to 4 hr post-exposure on each exposure day. Functional pulmonary responses to the pollutants were also characterized based on stratification by glutathione S-transferase mu 1 (GSTM1) genotype. On Day 1, exposure to air or DE did not change FEV1 or FVC in the subject population (n = 15). The co-exposure to O₃ and DE decreased FEV1 (17.6%) to a greater extent than O₃ alone (9.9%). To test for synergistic exposure effects, i.e., in a greater than additive fashion, FEV1 changes post individual O₃ and DE exposures were summed together and compared to the combined DE and O₃ exposure; the p value was 0.057. On Day 2, subjects who received DE exposure on Day 1 had a larger FEV1 decrement (14.7%) immediately after the O₃ exposure than the individuals' matched response following a Day 1 air exposure (10.9%). GSTM1 genotype did not affect the magnitude of lung function changes in a significant fashion. These data suggest that altered respiratory responses to the combination of O₃ and DE exposure can be observed showing a greater than additive manner. In addition, O₃-induced lung function decrements are greater with a prior exposure to DE compared to a prior exposure to filtered air. Based on the joint occurrence of these pollutants in the ambient environment, the potential exists for interactions in more than an additive fashion affecting lung physiological processes.
研究了稀释的全柴油废气（DE）和臭氧（O₃）（均为环境空气污染物混合物的常见成分）的组合对肺功能的潜在影响。健康的年轻人类志愿者在连续两天间歇性锻炼（约50升/分钟）的同时暴露于污染物中2小时。第1天的暴露分别为过滤空气、DE（300微克/立方米）、O₃（0.300 ppm）或两种污染物的组合。第2天所有暴露均为O₃（0.300 ppm），第3天作为随访观察日。在每个暴露日暴露前、暴露后立即以及暴露后4小时通过肺活量测定法评估肺功能。还根据谷胱甘肽S-转移酶μ1（GSTM1）基因型分层来表征对污染物的功能性肺反应。在第1天，暴露于空气或DE并未改变受试者群体（n = 15）的第一秒用力呼气容积（FEV1）或用力肺活量（FVC）。与单独暴露于O₃（9.9%）相比，同时暴露于O₃和DE使FEV1下降幅度更大（17.6%）。为了测试协同暴露效应，即以大于相加的方式，将个体暴露于O₃和DE后的FEV1变化相加，并与DE和O₃联合暴露进行比较；p值为0.057。在第2天，第1天接受DE暴露的受试者在暴露于O₃后立即出现的FEV1下降幅度（14.7%）大于第1天暴露于空气后的个体匹配反应（10.9%）。GSTM1基因型并未以显著方式影响肺功能变化的幅度。这些数据表明，可观察到对O₃和DE组合暴露的呼吸反应改变呈现出大于相加的方式。此外，与先前暴露于过滤空气相比，先前暴露于DE后O₃引起的肺功能下降幅度更大。基于这些污染物在环境中的共同存在，存在以大于相加的方式相互作用影响肺生理过程的可能性。
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