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Silicon dioxide nanoparticles (SiONPs), which are metal oxide nanoparticles, have been used in a wide variety of applications. In this study, acute pulmonary responses were examined after the intranasal instillation of SiONPs in mice primed with or without lipopolysaccharide (LPS, intranasal, 5 µg/mouse). The exposure to SiONPs increased the inflammatory cell counts and proinflammatory cytokines in the bronchoalveolar lavage fluid. SiONPs induced airway inflammation with increases in the phosphorylation of mitogen-activated protein kinases (MAPKs). The ratios of the inflammatory responses induced by the SiONPs were increased in the acute pulmonary disease model primed by LPS. Taken together, SiONPs exhibited toxicity to the respiratory system, which was associated with MAPK phosphorylation. In addition, the exposure to SiONPs exacerbated any existing inflammatory pulmonary diseases. These data showed the additive, as well as synergistic, interaction effects of SiONPs and LPS. We conclude that the exposure to SiONPs causes potential toxicity in humans, especially those with respiratory diseases.

Galgeun-tang water extract (GGWE) is used to treat various diseases such as the common cold, eczema and asthma in China and Korea. In this study, we investigated the anti-inflammatory effect of GGWE using a cigarette smoke (CS)- and lipopolysaccharide (LPS)-induced induced pulmonary inflammation mouse model. The mice were exposed to CS for a total of seven days (eight cigarettes per day for 1 h) and LPS was administered intranasally to mice on day 4. GGWE was administered by oral gavage at doses of 50 mg/kg or 100 mg/kg 1 h before exposure to CS. GGWE decreased inflammatory cell counts, and expression of inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α) in bronchoalveolar lavage fluid (BALF) from mice exposed to CS and LPS. GGWE reduced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), as well as the phosphorylation of inhibitor of kappa-B subunit alpha (IκBα) and nuclear factor kappa-B (NF-κB) in CS- and LPS-exposed mice. Histological examinations revealed that GGWE suppressed inflammatory cell infiltration into lung tissue compared to untreated CS- and LPS-exposed mice. In conclusion, GGWE effectively suppressed CS- and LPS-induced pulmonary inflammation. Our results indicate that GGWE may be used as a protective drug to control pulmonary inflammation diseases such as chronic obstructive pulmonary disease.