Warren D L, Last J A
Toxicol Appl Pharmacol. 1987 Apr;88(2):203-16. doi: 10.1016/0041-008x(87)90006-8.
Previously we have demonstrated that a synergistic interaction, as evaluated by several biochemical, toxicological, and morphological responses of the lung, results from exposure of rats to ozone (O3) in conjunction with moderate concentrations of acidic, but not neutral, aerosols. To extend these studies, groups of rats were continuously exposed to either O3 or sulfuric acid aerosol alone, or to combinations of these pollutants. Pulmonary responses from these rats were measured by assay, after exposures for 6 hr to 7 days, of total lavageable protein content, total lung tissue protein content after 5, 7, or 9 days of exposure, or apparent collagen synthesis rates from lung tissue after 7 days of exposure. While the lavageable protein content from rats exposed for 3 days to 0.1 or 1.0 mg/m3 of sulfuric acid aerosol alone was not different from control values, significant elevations from control values were observed from groups exposed to 0.12, 0.20, or 0.64 ppm of O3. Synergy was demonstrated by this assay upon exposure of rats to 0.20 ppm of O3 in conjunction with 0.1, 0.5, or 1.0 mg/m3 of sulfuric acid aerosol. Similarly, the tissue protein content from rats exposed to 0.1 or 1.0 mg/m3 of sulfuric acid aerosol alone was indistinguishable from control values. Significant elevations from control values were observed by this assay from groups of rats exposed to 0.64 or 0.20 ppm of O3, and a synergistic interaction was demonstrated between 0.64 ppm of O3 and 1.0 mg/m3 of sulfuric acid aerosol. Furthermore, synergy was observed by quantification of increased total lung protein between 0.20 ppm of O3 + 40 micrograms/m3 and higher concentrations of sulfuric acid aerosol. Values of the lung collagen synthesis rate from rats exposed to 0.1, but not 1.0, 0.5, or 0.04 mg/m3 of sulfuric acid aerosol were significantly higher than values from lungs of control animals. Significant elevations from control values were also observed by this assay from groups of rats exposed to 0.64 or 0.20 ppm of O3. A synergistic interaction was demonstrated by the collagen synthesis rate assay between groups of rats exposed to 0.64 ppm of O3 + 0.20 mg/m3 and higher concentrations of sulfuric acid aerosol or between groups exposed to 0.20 ppm of O3 + 40 micrograms/m3 and higher concentrations of sulfuric acid aerosol. These results demonstrate synergy between O3 and sulfuric acid aerosol upon exposure to concentrations of each pollutant at or near peak hourly ambient levels in polluted urban atmospheres.
此前我们已经证明，通过对肺部的几种生化、毒理学和形态学反应评估，大鼠暴露于臭氧（O₃）并结合中等浓度的酸性而非中性气溶胶时会产生协同相互作用。为了扩展这些研究，将几组大鼠分别持续暴露于单独的O₃或硫酸气溶胶，或这些污染物的组合中。在暴露6小时至7天后，通过检测总可灌洗蛋白含量、暴露5、7或9天后的全肺组织蛋白含量，或暴露7天后肺组织的表观胶原蛋白合成率来测量这些大鼠的肺部反应。虽然仅暴露于0.1或1.0 mg/m³硫酸气溶胶3天的大鼠的可灌洗蛋白含量与对照值无差异，但暴露于0.12、0.20或0.64 ppm O₃的组中观察到与对照值相比有显著升高。当大鼠暴露于0.20 ppm O₃并结合0.1、0.5或1.0 mg/m³硫酸气溶胶时，该检测方法证明了协同作用。同样，仅暴露于0.1或1.0 mg/m³硫酸气溶胶的大鼠的组织蛋白含量与对照值无差异。通过该检测方法，在暴露于0.64或0.20 ppm O₃的大鼠组中观察到与对照值相比有显著升高，并且在0.64 ppm O₃和1.0 mg/m³硫酸气溶胶之间证明了协同相互作用。此外，通过量化0.20 ppm O₃ + 40微克/m³与更高浓度硫酸气溶胶之间全肺蛋白增加量观察到了协同作用。暴露于0.1 mg/m³硫酸气溶胶（而非1.0、0.5或0.04 mg/m³）的大鼠的肺胶原蛋白合成率值显著高于对照动物肺的值。通过该检测方法，在暴露于0.64或0.20 ppm O₃的大鼠组中也观察到与对照值相比有显著升高。在暴露于0.64 ppm O₃ + 0.20 mg/m³与更高浓度硫酸气溶胶的大鼠组之间，或在暴露于0.20 ppm O₃ + 40微克/m³与更高浓度硫酸气溶胶的大鼠组之间，胶原蛋白合成率检测方法证明了协同相互作用。这些结果表明，在污染城市大气中，当每种污染物暴露浓度处于或接近每小时峰值环境水平时，O₃与硫酸气溶胶之间存在协同作用。
