title: Radix puerariae extracts ameliorate paraquat-induced pulmonary fibrosis by attenuating follistatin-like 1 and nuclear factor erythroid 2p45-related factor-2 signalling pathways through downregulation of miRNA-21 expression.
abstract: BACKGROUND
  Puerarin, extracted from Radix puerariae, was reported to ameliorate airway inflammation, lung injury and lung fibrosis induced by paraquat (PQ) in mice. However, effects of Radix puerariae extracts (RPEs) on lung fibrosis or signalling pathways in PQ-induced lung injury have not been well studied. Therefore, the goals of our study were to investigate whether Radix puerariae extracts are antifibrotic in a paraquat (PQ) induced lung fibrosis model in mice and to propose possible mechanisms of action of the RPE effects.
  
  
  METHODS
  We used a long-term exposure model of PQ-induced lung fibrosis in mice to evaluate effects of antioxidant-containing RPE. We examined effects of miR-21 on follistatin-like 1 (Fstl 1) pathways and oxidative stress in the lung. Gene expression levels of miR-21, Fstl 1, transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), collagen-1 and collagen III were measured by real-time PCR. Protein expression levels of Fstl 1(FSTL1), heme oxygenase-1 (HO-1), nuclear factor erythroid 2p45-related factor-2 (Nrf2), Smad2/3, p38MAPK, nuclear factor-κB 65 (NF-κB65), and matrix metalloproteinase-9 were detected by western blotting. FSTL1 andalpha-smooth muscle actin (α-SMA) in lung tissue were detected by immunohistochemistry. Malondialdehyde, superoxide dismutase (SOD), reduced (GSH) and oxidised (GSSH) glutathione and reactive oxygen species levels, hydroxyproline and total lung collagen were also determined.
  
  
  RESULTS
  Long-term challenge with PQ enhanced miRNA-21 (miR-21), Fstl 1 pathways, oxidative stress and development of fibrotic features in the lungs. RPE reduced features of lung fibrosis by blocking Fstl 1 pathways and oxidative stress through decreased miR-21 expression. This was accompanied by suppression of CTGF, TGF-β1, vascular endothelial growth factor, collagen I, and collagen III. In addition, PQ-induced activation of NF-κB, Nrf2 and α-SMA were enhanced by puerarin. We also found that puerarin increased HO-1, SOD and GSH levels.
  
  
  CONCLUSIONS
  These findings demonstrated that RPEs blocked PQ-induced Fstl 1 pathways and oxidative stress by inhibiting miR-21 expression, leading to attenuation of PQ-induced lung fibrosis.
authors.affiliation: Department of Emergency, the First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Wu Hua District, Kunming, 650032, China.
authors.forename: Ming-Wei
authors.initials: MW
authors.lastname: Liu
authors.affiliation: Department of Emergency, the First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Wu Hua District, Kunming, 650032, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Liu
authors.affiliation: Department of Emergency, the First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Wu Hua District, Kunming, 650032, China.
authors.forename: Hai-Ying
authors.initials: HY
authors.lastname: Wu
authors.affiliation: Department of Emergency, the First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Wu Hua District, Kunming, 650032, China.
authors.forename: Yi-Yun
authors.initials: YY
authors.lastname: Li
authors.affiliation: Emergency Intensive Care Unit, the Second Affiliated Hospital of Kunming Medical University, Kunming, 650106, China.
authors.forename: Mei-Xian
authors.initials: MX
authors.lastname: Su
authors.affiliation: Department of Emergency, the First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Wu Hua District, Kunming, 650032, China.
authors.forename: Min-Na
authors.initials: MN
authors.lastname: Dong
authors.affiliation: Department of Emergency, the First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Wu Hua District, Kunming, 650032, China. zhangwei7222@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Emergency, the First Affiliated Hospital of Kunming Medical University, 295 Xichang Road, Wu Hua District, Kunming, 650032, China. qianchuayun@126.com.
authors.forename: Chuan-Yun
authors.initials: CY
authors.lastname: Qian
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000627:therapeutic use; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D015536:Down-Regulation; D004365:Drugs, Chinese Herbal / Q000627:therapeutic use*; D038702:Follistatin-Related Proteins / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006540:Herbicides / Q000633:toxicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D010269:Paraquat / Q000633:toxicity*; D029908:Pueraria; D011658:Pulmonary Fibrosis / Q000139:chemically induced* / Q000188:drug therapy*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000975:Antioxidants; D004365:Drugs, Chinese Herbal; D038702:Follistatin-Related Proteins; C448720:Fstl1 protein, mouse; D006540:Herbicides; C531950:MIRN21 microRNA, mouse; D035683:MicroRNAs; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D017382:Reactive Oxygen Species; C442842:plant extract, Puerariae Radix; D003094:Collagen; D010269:Paraquat