Effective fraction of Bletilla striata reduces the inflammatory cytokine production induced by water and organic extracts of airborne fine particulate matter (PM2.5) in vitro

Yu-Yao Zu,Quan-Fang Liu,Fu-Sheng Jiang,Mei-Ya Li,Li-Xia Jin,Bing-Qi Zhu,Shu-Xin Tian,Zhi-Shan Ding

doi:10.1186/s12906-019-2790-3

Abstract

BackgroundBletilla striata is a traditional Chinese medicine used to treat hemorrhage, scald, gastric ulcer, pulmonary diseases and inflammations. In this study, we investigated bioactivity of the effective fraction of B. striata (EFB) in reducing the inflammatory cytokine production induced by water or organic extracts of PM2.5.MethodsPM2.5 extracts were collected and analyzed by chromatographic system and inductively coupled plasma mass spectrometer. Cell viability was measured using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay, and cell supernatant was analyzed by flow cytometry, ELISA, and qRT-PCR in cultured mouse macrophage cell line RAW264.7 treated with EFB and PM2.5 extracts. Expressions of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathway were measured by Western blot.ResultsPM2.5 composition is complex and the toxicity of PM2.5 extracts were not noticeable. The treatment of EFB at a wide dose-range of 0–40 μg/mL did not cause significant change of RAW264.7 cell proliferation. EFB pretreatment decreased the inflammatory cytokines in the macrophage. Further analysis showed that EFB significantly attenuated PM2.5-induced proinflammatory protein expression and downregulated the levels of phosphorylated NF-κBp65, inhibitor of kappa B (IκB)-α, c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38.ConclusionsOur study demonstrated the potential effectiveness of B. striata extracts for treating PM2.5-triggered pulmonary inflammation.

Highlights

Bletilla striata is a traditional Chinese medicine used to treat hemorrhage, scald, gastric ulcer, pulmonary diseases and inflammations
Harvested proteins were denatured at 95 °C for 10 min, separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDSPAGE), and transferred onto a polyvinylidene fluoride (PVDF) membrane (Millipore Corp., USA)
PM2.5 water or organic extract induced phosphorylation of mitogen-activated protein kinase (MAPK) family protein extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK) and p38 level which was notably attenuated by B. striata total ethanol-extract (BTE) or Coelonin pretreatment (Fig. 9). These results suggest that BTE or Coelonin significantly alleviated the activation of MAPK cascade, and mitigated the nuclear factor-kappa B (NF-κB) binding through prevention of PM2.5 extracts induced

Summary

Introduction

Bletilla striata is a traditional Chinese medicine used to treat hemorrhage, scald, gastric ulcer, pulmonary diseases and inflammations. We investigated bioactivity of the effective fraction of B. striata (EFB) in reducing the inflammatory cytokine production induced by water or organic extracts of PM2.5. Mitogen-activated protein kinase (MAPK), including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 kinase, are activated in PM2.5-treated macrophages [9,10,11]. Activated MAPK can upregulate inflammatory cytokine expression via phosphorylation of the downstream transcription factor, activator protein-1 (AP-1). The NF-κB and MAPK pathways are key targets for the treatment of PM2.5induced pulmonary inflammation and dysfunction [12]

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Conclusion