Ambient PM2.5 exposure exacerbates severity of allergic asthma in previously sensitized mice. (14th September 2015)

• Record Type: Journal Article
• Authors: Zhang, Xingliang; Zhong, Wenqing; Meng, Qingqi; Lin, Qianwen; Fang, Chao; Huang, Xiulan; Li, Chengyan; Huang, Yuge; Tan, Jianxin
• Is Part Of: Journal of asthma. Volume 52:Number 8(2015)
• Page Start: 785
• Page End: 794
• Publication Date: 2015-09-14
• Subjects: Ambient particulate matter -- asthma -- airway hyper-responsiveness -- pulmonary inflammation -- lung lesion -- OVA-sensitization/challenge model; Asthma -- Periodicals; 616.238005
• DOI: 10.3109/02770903.2015.1036437
• Languages: English
• ISSNs: 0277-0903

Abstract

Abstract: Objective : Epidemiological studies have shown that elevated concentrations of ambient particulate matter (aerodynamic diameter ≤2.5 μm; PM2.5) correlates with increased incidence of asthma. The aim of this study was to determine whether PM2.5 participates in the exacerbation of asthma. Methods : Effects of 1, 10 and 100 μg PM2.5 instilled intratracheally in ovalbumin (OVA)-sensitized or asthmatic mice were compared. Results : PM2.5 exposure in the OVA-sensitized and especially asthmatic groups increased Mch responsiveness in a dose-dependent manner. In OVA-sensitized groups, exposure to 1 μg of PM2.5 caused no detectable lung inflammation, while 10 and 100 μg of PM2.5 resulted in a slightly increased trend in numbers of neutrophils and macrophages. Compared with the asthmatic control group, both 10 and 100 μg of PM2.5 provoked a significant increase in eosnophils and neutrophils whereas only 100 μg of PM2.5 noticeably enhanced lymphocytes. In asthmatic groups, administration of 100 μg of PM2.5 greatly increased levels of the pro-inflammatory cytokine TNF-α and Th2-related cytokines IL-4 and IL-10 in bronchoalveolar lavage fluid, but it decreased Th1-related INF-γ. In addition, 10 and 100 μg of PM2.5 exacerbated inflammatory infiltration, goblet cell metaplasia and lung ultrastructure lesions in asthmatic mice. Conclusions : Our results suggested that acute exposure of PM2.5 could synergize with allergens in the subsequent challenge to aggravate the severity of asthma in sensitized mice, possibly by promoting a Th2-biased immune response.