背景:交通衍生的颗粒是对环境颗粒物(PM)的不利健康影响的重要贡献者。在北欧国家,路面矿物颗粒和柴油机废气颗粒(DEP)是交通PM的重要成分。在本研究中,我们比较了两个公路隧道中矿物颗粒和DEP对PM的促炎反应,并检查了其中的机制。
方法:100µg/mL粗粒(PM10-2.5)的促炎潜能,在人支气管上皮细胞(HBEC3-KT)中评估了在两个用不同石头材料铺设的公路隧道中采样的细PM(PM2.5-0.18)和超细PM(PM0.18),并与DEP和来自各自石材的颗粒进行比较。促炎细胞因子的释放(CXCL8,IL-1α,IL-1β)通过ELISA测量,而与炎症相关的基因(COX2,CXCL8,IL-1α,IL-1β,TNF-α),通过qPCR确定氧化还原反应(HO-1)和代谢(CYP1A1,CYP1B1,PAI-2)。通过用AhR抑制剂CH223191和抗氧化剂N-乙酰半胱氨酸(NAC)处理来检查芳烃受体(AhR)和活性氧(ROS)的作用。
结果:公路隧道PM引起CXCL8,COX2,IL-1α表达的时间依赖性增加,IL-1β,TNF-α,COX2,PAI-2,CYP1A1,CYP1B1和HO-1,在早期时间点,细PM比粗PM更有效。对于一个隧道,结石颗粒样品和DEP诱导的细胞因子释放低于所有大小分级的PM样品,和另一条隧道的好PM。对于细PM和粗PM,CH223191部分降低IL-1α和CXCL8的释放和表达以及COX2的表达,取决于隧道,响应和时间点。虽然CYP1A1的表达被CH223191显著降低,但HO-1的表达不受影响。NAC降低IL-1α和CXCL8的释放和表达,降低COX2的表达,但CYP1A1和HO-1的表达增加。
结论:结果表明,公路隧道PM在HBEC3-KT细胞中的促炎反应并非仅归因于矿物颗粒或DEP。促炎反应似乎涉及AhR依赖性机制,暗示了有机成分的作用。ROS介导的机制也参与其中,可能是通过不依赖AhR的途径。DEP可能是AhR依赖性反应的贡献者,尽管其他来源可能很重要。
Traffic-derived particles are important contributors to the adverse health effects of ambient particulate matter (PM). In Nordic countries, mineral particles from road pavement and diesel exhaust particles (DEP) are important constituents of traffic-derived PM. In the present study we compared the pro-inflammatory responses of mineral particles and DEP to PM from two road tunnels, and examined the mechanisms involved.
The pro-inflammatory potential of 100 µg/mL coarse (PM10-2.5), fine (PM2.5-0.18) and ultrafine PM (PM0.18) sampled in two road tunnels paved with different stone materials was assessed in human bronchial epithelial cells (HBEC3-KT), and compared to DEP and particles derived from the respective stone materials. Release of pro-inflammatory cytokines (CXCL8, IL-1α, IL-1β) was measured by ELISA, while the expression of genes related to inflammation (COX2, CXCL8, IL-1α, IL-1β, TNF-α), redox responses (HO-1) and metabolism (CYP1A1, CYP1B1, PAI-2) was determined by qPCR. The roles of the aryl hydrocarbon receptor (AhR) and reactive oxygen species (ROS) were examined by treatment with the AhR-inhibitor CH223191 and the anti-oxidant N-acetyl cysteine (NAC).
Road tunnel PM caused time-dependent increases in expression of CXCL8, COX2, IL-1α, IL-1β, TNF-α, COX2, PAI-2, CYP1A1, CYP1B1 and HO-1, with fine PM as more potent than coarse PM at early time-points. The stone particle samples and DEP induced lower cytokine release than all size-fractionated PM samples for one tunnel, and versus fine PM for the other tunnel. CH223191 partially reduced release and expression of IL-1α and CXCL8, and expression of COX2, for fine and coarse PM, depending on tunnel, response and time-point. Whereas expression of CYP1A1 was markedly reduced by CH223191, HO-1 expression was not affected. NAC reduced the release and expression of IL-1α and CXCL8, and COX2 expression, but augmented expression of CYP1A1 and HO-1.
The results indicate that the pro-inflammatory responses of road tunnel PM in HBEC3-KT cells are not attributed to the mineral particles or DEP alone. The pro-inflammatory responses seem to involve AhR-dependent mechanisms, suggesting a role for organic constituents. ROS-mediated mechanisms were also involved, probably through AhR-independent pathways. DEP may be a contributor to the AhR-dependent responses, although other sources may be of importance.