ABSTRACT

Wildland fires (WF) are linked to adverse health impacts related to poor air quality. The cardiovascular impacts of emissions from specific biomass sources are however unknown. The purpose of this study was to assess the cardiovascular impacts of a single exposure to peat smoke, a key regional WF air pollution source, and relate these to baroreceptor sensitivity and inflammation. Three-month-old male Wistar-Kyoto rats, implanted with radiotelemeters for continuous monitoring of heart rate (HR), blood pressure (BP), and spontaneous baroreflex sensitivity (BRS), were exposed once, for 1-hr, to filtered air or low (0.38 mg/m³ PM) or high (4.04 mg/m³) concentrations of peat smoke. Systemic markers of inflammation and sensitivity to aconitine-induced cardiac arrhythmias, a measure of latent myocardial vulnerability, were assessed in separate cohorts of rats 24 hr after exposure. PM size (low peat = 0.4–0.5 microns vs. high peat = 0.8–1.2 microns) and proportion of organic carbon (low peat = 77% vs. high peat = 65%) varied with exposure level. Exposure to high peat and to a lesser extent low peat increased systolic and diastolic BP relative to filtered air. In contrast, only exposure to low peat elevated BRS and aconitine-induced arrhythmogenesis relative to filtered air and increased circulating levels of low-density lipoprotein cholesterol, complement components C3 and C4, angiotensin-converting enzyme (ACE), and white blood cells. Taken together, exposure to peat smoke produced overt and latent cardiovascular consequences that were likely influenced by physicochemical characteristics of the smoke and associated adaptive homeostatic mechanisms.

摘要

野火 (WF) 与空气质量差对健康造成的不利影响有关。然而，特定生物质来源的排放对心血管的影响尚不清楚。本研究的目的是评估单次暴露于泥炭烟雾（一种主要的区域 WF 空气污染源）对心血管的影响，并将这些影响与压力感受器敏感性和炎症联系起来。三个月大的雄性 Wistar-Kyoto 大鼠，植入无线电遥测仪以连续监测心率 (HR)、血压 (BP) 和自发压力反射敏感性 (BRS)，暴露在过滤空气中一次，持续 1 小时或低 (0.38 mg/m ³ PM) 或高 (4.04 mg/m ³) 泥炭烟雾的浓度。在暴露后 24 小时，在不同的大鼠队列中评估了炎症的全身标志物和对乌头碱诱发的心律失常的敏感性，这是一种衡量潜在心肌脆弱性的指标。PM 大小（低泥炭 = 0.4-0.5 微米与高泥炭 = 0.8-1.2 微米）和有机碳比例（低泥炭 = 77% 对高泥炭 = 65%）随暴露水平而变化。相对于过滤空气，暴露于高泥炭和较小程度上的低泥炭会增加收缩压和舒张压。相比之下，与过滤空气相比，仅暴露于低泥炭会增加 BRS 和乌头碱诱发的心律失常，并增加低密度脂蛋白胆固醇、补体成分 C3 和 C4、血管紧张素转换酶 (ACE) 和白细胞的循环水平。综合起来，