Rose R M, Fuglestad J M, Skornik W A, Hammer S M, Wolfthal S F, Beck B D, Brain J D
Department of Medicine, New England Deaconess Hospital, Boston, MA 02215.
Am Rev Respir Dis. 1988 Apr;137(4):912-7. doi: 10.1164/ajrccm/137.4.912.
To determine whether exposure to nitrogen dioxide (NO2) affects respiratory tract susceptibility to viral infection, CD-1 mice were inoculated intratracheally with murine cytomegalovirus (MCMV) during exposure to varying concentrations of NO2. Exposure lasted for 6 h per day; it began 2 consecutive days prior to instillation of MCMV and continued for 4 days after virus inoculation. Exposure to 5 ppm NO2 resulted in MCMV proliferation and a mild bronchopneumonia in some animals inoculated with 10(2) plaque-forming units of virus. Importantly, this inoculum was too low to produce either viral replication or histologic abnormalities in the lungs of air-exposed animals. We also found that the amount of virus required to infect animals exposed to 5 ppm of NO2 was 100-fold lower than that needed to consistently produce infection in air-exposed animals. Animals exposed to 5 ppm NO2 also exhibited depressed phagocytosis of colloidal Au198 in vivo as well as diminished macrophage destruction of instilled MCMV compared to air-exposed animals. These results demonstrate that exposure to 5 ppm NO2, although not associated with evidence of overt lung injury per se, is nevertheless capable of predisposing the lower respiratory tract to viral infection.
为了确定接触二氧化氮（NO₂）是否会影响呼吸道对病毒感染的易感性，在接触不同浓度的NO₂期间，对CD-1小鼠进行气管内接种鼠巨细胞病毒（MCMV）。每天接触持续6小时；在接种MCMV前连续2天开始接触，并在病毒接种后持续4天。接触5 ppm的NO₂导致在接种10²个空斑形成单位病毒的一些动物中出现MCMV增殖和轻度支气管肺炎。重要的是，这个接种量过低，以至于在暴露于空气的动物肺中不会产生病毒复制或组织学异常。我们还发现，感染接触5 ppm NO₂动物所需的病毒量比持续感染暴露于空气动物所需的病毒量低100倍。与暴露于空气的动物相比，接触5 ppm NO₂的动物在体内对胶体金¹⁹⁸的吞噬作用也受到抑制，并且对注入的MCMV的巨噬细胞破坏作用减弱。这些结果表明，接触5 ppm NO₂虽然本身与明显的肺损伤证据无关，但仍能够使下呼吸道易患病毒感染。
