Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, 109 TW. Alexander Dr., Research Triangle Park, NC, 27711, USA.
Exposure Methods and Measurements Division, National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC, USA.
Cardiovasc Toxicol. 2018 Dec;18(6):569-578. doi: 10.1007/s12012-018-9469-8.
The health effects of individual criteria air pollutants have been well investigated. However, little is known about the health effects of air pollutant mixtures that more realistically represent environmental exposures. The present study was designed to evaluate the cardiac effects of inhaled simulated smog atmospheres (SA) generated from the photochemistry of either gasoline and isoprene (SA-G) or isoprene (SA-Is) in mice. Four-month-old female mice were exposed for 4 h to filtered air (FA), SA-G, or SA-Is. Immediately and 20 h after exposure, cardiac responses were assessed with a Langendorff preparation using a protocol consisting of 20 min of global ischemia followed by 2 h of reperfusion. Cardiac function was measured by index of left-ventricular developed pressure (LVDP) and cardiac contractility (dP/dt) before ischemia. Pre-ischemic LVDP was lower in mice immediately after SA-Is exposure (52.2 ± 5.7 cm HO compared to 83.9 ± 7.4 cm HO after FA exposure; p = 0.008) and 20 h after SA-G exposure (54.0 ± 12.7 cm HO compared to 79.3 ± 7.4 cm HO after FA exposure; p = 0.047). Pre-ischemic left ventricular contraction dP/dt was lower in mice immediately after SA-Is exposure (2025 ± 169 cm HO/sec compared to 3044 ± 219 cm HO/sec after FA exposure; p < 0.05) and 20 h after SA-G exposure (1864 ± 328 cm HO/sec compared to 2650 ± 258 cm HO/sec after FA exposure; p = 0.05). In addition, SA-G reduced the coronary artery flow rate 20 h after exposure compared to the FA control. This study demonstrates that acute SA-G and SA-Is exposures decrease LVDP and cardiac contractility in mice, indicating that photochemically-altered atmospheres affect the cardiovascular system.
个体空气污染物标准对健康的影响已经得到了充分的研究。然而，对于更真实地反映环境暴露的空气污染物混合物对健康的影响，人们知之甚少。本研究旨在评估吸入由汽油和异戊二烯（SA-G）或异戊二烯（SA-Is）的光化学反应产生的模拟烟雾大气（SA）对小鼠的心脏影响。四个月大的雌性小鼠暴露于过滤空气（FA）、SA-G 或 SA-Is 中 4 小时。暴露后立即和 20 小时，使用包括 20 分钟整体缺血和 2 小时再灌注的方案，通过 Langendorff 制剂评估心脏反应。缺血前通过左心室发展压（LVDP）指数和心脏收缩性（dP/dt）测量心脏功能。SA-Is 暴露后立即，小鼠的左心室收缩前 LVDP 降低（52.2±5.7 cm HO 与 FA 暴露后 83.9±7.4 cm HO 相比；p=0.008）和 20 小时后 SA-G 暴露（54.0±12.7 cm HO 与 FA 暴露后 79.3±7.4 cm HO 相比；p=0.047）。SA-Is 暴露后立即，左心室收缩前 dP/dt 降低（2025±169 cm HO/sec 与 FA 暴露后 3044±219 cm HO/sec 相比；p<0.05）和 20 小时后 SA-G 暴露（1864±328 cm HO/sec 与 FA 暴露后 2650±258 cm HO/sec 相比；p=0.05）。此外，SA-G 暴露 20 小时后降低了冠状动脉流量，与 FA 对照组相比。本研究表明，急性 SA-G 和 SA-Is 暴露降低了小鼠的 LVDP 和心脏收缩性，表明光化学改变的大气会影响心血管系统。
