Organic acid component from Taraxacum mongolicum Hand.-Mazz alleviates inflammatory injury in lipopolysaccharide-induced acute tracheobronchitis of ICR mice through TLR4/NF-κB signaling pathway

Int Immunopharmacol. 2016 May;34:92-100. doi: 10.1016/j.intimp.2016.02.028. Epub 2016 Feb 28.

Abstract

Inflammation plays an important role in the pathogenesis of acute tracheobronchitis. Taraxacum mongolicum Hand.-Mazz (TMHM) is a dietic herb for heat-clearing and detoxifying functions as well as swell-reducing and mass-resolving effect in Traditional Chinese Medicine. Studies have shown that its major ingredient organic acid component (OAC) possesses favorable anti-inflammatory activity. However, the protective effect of OAC from TMHM (TMHM-OAC) on inflammatory injury of acute tracheobronchitis and its possible mechanism remains poorly understood. In this study, HPLC-DAD was used to analyze the components of TMHM-OAC. Lipopolysaccharide of 1mg/ml was used to induce respiratory inflammation in ICR mice at the dose of 5mg/kg by intratracheally aerosol administration. Enzyme-linked immunosorbent assay (ELISA) was employed to detect the levels of inflammation factors such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and nitric oxide in serum and supernatant of trachea tissue. Western blotting (WB) and Immunohistochemistry analysis (IHC) were conducted in parallel to determine TNF-α, IL-6, inducible nitric oxide synthase (iNOS), Toll-like receptors 4(TLR4) protein expressions and nuclear factor-kappa B p65 (NF-κB p65) phosphorylation. Hematoxylin-Eosin staining (HE) was applied to evaluate pathological lesions of trachea tissue. Experimental results showed that TMHM-OAC significantly reduced the levels of the TNF-α, IL-6 and NO in serum and supernatant of tracheal of LPS-induced ICR mice. The protein expression levels of TNF-α, IL-6 and iNOS in tracheal tissue were also down-regulated significantly by the treatment of TMHM-OAC. Moreover, TMHM-OAC downregulated phosphorylation of NF-κB p65 and protein expression of TLR4. Our results indicated that TMHM-OAC could improve LPS-induced histopathological damage of tracheal tissues through the regulation of TLR4/NF-κB signaling pathway and could be beneficial for the treatment of acute tracheobronchitis.

Keywords: Acute tracheobronchitis; Anti-inflammation; Organic acid component; Taraxacum mongolicum Hand.-Mazz.

MeSH terms

  • Acute Disease
  • Animals
  • Bronchitis / drug therapy*
  • Bronchitis / immunology
  • Cells, Cultured
  • Drugs, Chinese Herbal / therapeutic use*
  • Gene Expression Regulation / drug effects
  • Humans
  • Interleukin-6 / metabolism
  • Lipopolysaccharides / immunology
  • Male
  • Mice
  • Mice, Inbred ICR
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type II / metabolism
  • Signal Transduction / drug effects
  • Taraxacum / immunology
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism*
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Drugs, Chinese Herbal
  • Interleukin-6
  • Lipopolysaccharides
  • NF-kappa B
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4
  • Tumor Necrosis Factor-alpha
  • Nitric Oxide Synthase Type II