Oregon Health & Science University-Portland State University School of Public Health, 506 SW Mill St., Suite 450, Portland, OR, 97201, USA.
Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, 615 N. Wolfe St., Baltimore, MD, 21205, USA.
Cardiovasc Toxicol. 2018 Dec;18(6):507-519. doi: 10.1007/s12012-018-9461-3.
Exposure to ambient particulate matter (PM) is associated with increased cardiac morbidity and mortality with the elderly considered to be the most susceptible. The purpose of this study was to determine if exposure to PM would cause a greater impact on heart regulation in older DBA/2 (D2) male mice as determined by changes in heart rate (HR) and heart rate variability (HRV). D2 mice at the ages of 4, 12, and 19 months were instilled with 100 µg of PM or saline by aspiration. Before and after the aspiration, 3-min echocardiogram (ECG) samples for HR and HRV were recorded at 15-min intervals for 3 h along with corresponding measurements of homeostasis, such as temperature, metabolism, and ventilation. PM exposure resulted in an increase in HRV, declines in HR, and altered measures of homeostasis for a subset of the 12-mo mice. The PM aspiration did not affect cardiac or homeostasis parameters in the 4- or 19-mo mice. Our results suggest that a select group of middle-age mice are more susceptible to alterations in their heart rhythm after PM exposure and highlight that there are acute age-related differences in heart rhythm following PM exposure.
暴露于环境颗粒物（PM）与心脏发病率和死亡率的增加有关，老年人被认为是最易受影响的人群。本研究的目的是确定暴露于 PM 是否会对老年 DBA/2（D2）雄性小鼠的心脏调节产生更大的影响，这可以通过心率（HR）和心率变异性（HRV）的变化来确定。4、12 和 19 月龄的 D2 小鼠通过抽吸分别接受 100µg 的 PM 或盐水。在抽吸前后，每隔 15 分钟记录 3 分钟的超声心动图（ECG）样本，以记录 HR 和 HRV，同时还记录了体温、代谢和通气等与生理平衡相关的相应测量值。PM 暴露导致一部分 12 月龄小鼠的 HRV 增加、HR 下降和生理平衡测量值改变。PM 抽吸对 4 或 19 月龄的小鼠的心脏或生理平衡参数没有影响。我们的研究结果表明，一组特定的中年小鼠在 PM 暴露后更容易出现心律改变，并且强调了 PM 暴露后心率随年龄变化的急性差异。
