Depuydt P O, Lambrecht B N, Joos G F, Pauwels R A
Department of Respiratory Diseases, Ghent University Hospital, Ghent, Belgium.
Clin Exp Allergy. 2002 Mar;32(3):391-6. doi: 10.1046/j.1365-2222.2002.01364.x.
Epidemiological studies suggest that ozone exposure is related to increased asthma symptoms. Dendritic cells (DCs) are the principal antigen-presenting cells in the airways.
We have examined whether ambient doses of ozone (100 ppb for 2 h) enhance allergic sensitization and/or airway inflammation in a mouse model.
C57BL/6 mice were sensitized to inhaled ovalbumin (OVA) by intratracheal instillation of OVA-pulsed DCs on day 0. Daily exposure to OVA aerosol on days 14-20 resulted in an eosinophilic airway inflammation, as reflected in bronchoalveolar lavage fluid and lung histology. In a first experiment, mice were exposed to ozone or room air immediately prior to and following sensitization. Subsequently, we tested the effect of ozone exposure during antigen challenge in DC-sensitized mice.
Exposure to ozone during sensitization did not influence airway inflammation after subsequent allergen challenge. In contrast, in sensitized mice, challenge with OVA together with ozone (days 14-20) resulted in enhanced airway eosinophilia and lymphocytosis, as compared with mice exposed to OVA and room air (1.91 x 106 +/- 0.46 x 106 vs. 0.16 x 106 +/- 0.06 x 106 eosinophils/mL lavage fluid; P = 0.015; 0.49 x 106 +/- 0.11 x 106 vs. 0.08 x 106 +/- 0.03 x 106 lymphocytes/mL lavage fluid; P = 0.004). Ozone exposure without subsequent OVA exposure did not cause airway inflammation.
Ozone exposure does not increase allergic sensitization but enhances antigen-induced airway inflammation in mice that are sensitized via the airways.
流行病学研究表明，接触臭氧与哮喘症状加重有关。树突状细胞（DCs）是气道中的主要抗原呈递细胞。
我们研究了环境剂量的臭氧（100 ppb，持续2小时）是否会增强小鼠模型中的过敏性致敏和/或气道炎症。
在第0天，通过气管内注入卵清蛋白（OVA）脉冲DCs使C57BL/6小鼠对吸入的OVA致敏。在第14 - 20天每天暴露于OVA气雾剂导致嗜酸性气道炎症，这在支气管肺泡灌洗液和肺组织学中有所体现。在第一个实验中，小鼠在致敏前后立即暴露于臭氧或室内空气。随后，我们测试了在DC致敏小鼠的抗原激发过程中臭氧暴露的影响。
致敏期间接触臭氧对随后的过敏原激发后的气道炎症没有影响。相比之下，在致敏小鼠中，与暴露于OVA和室内空气的小鼠相比，OVA与臭氧一起激发（第14 - 20天）导致气道嗜酸性粒细胞增多和淋巴细胞增多增强（灌洗液中嗜酸性粒细胞：1.91×10⁶±0.46×10⁶对0.16×10⁶±0.06×10⁶/mL；P = 0.015；灌洗液中淋巴细胞：0.49×10⁶±0.11×10⁶对0.08×10⁶±0.03×10⁶/mL；P = 0.004）。无后续OVA暴露的臭氧暴露未引起气道炎症。
臭氧暴露不会增加过敏性致敏，但会增强通过气道致敏的小鼠中抗原诱导的气道炎症。
