title: Low dose pirfenidone suppresses transforming growth factor beta-1 and tissue inhibitor of metalloproteinase-1, and protects rats from lung fibrosis induced by bleomycina.
abstract: OBJECTIVE
  To investigate the optimal dosage of pirfenidone for the treatment of pulmonary fibrosis induced by bleomycin in Wistar rats, and the alteration of expressions of transforming growth factor beta-1 (TGF-beta 1), tissue inhibitor of metalloproteinase-1 (TIMP-1), and matrix metalloproteinase-13 (MMP-13) in lung tissue.
  
  
  METHODS
  Male Wistar rats were endotracheally instilled with bleomycin or normal saline. Pirfenidone (25-800 mg x kg(-1) x d(-1)), dexamethasone (3 mg/kg), or 1% carboxymethylcellulose sodium were given daily by feed 2 days before instillation of bleomycin. Groups T7 and T14 were fed pirfenidone 50 mg x kg(-1) x d(-1) at 7 days or 14 days after bleomycin instillation. Lungs were harvested at 28 days after bleomycin instillation. Patholological changes in lung tissues were evaluated with HE staining. Lung collagen was stained by sirius red and measured by content of hydroxyproline. Expression of proteins of TGF-beta 1, TIMP-1, and MMP-13 were detected by Western blotting.
  
  
  RESULTS
  At doses of 25, 50, and 100 mg x kg(-1) x d(-1), pirfenidone had significant anti-fibrotic effects for bleomycin-induced rat pulmonary fibrosis, and these effects were most significantly attenuated at the dosage of 50 mg x kg(-1) x d(-1) (HE: P < 0.01, P < 0.01, and P = 0.064; sirius red: P < 0.05, P < 0.01, and P < 0.05; hydroxyproline: P = 0.595, P < 0.01, and P = 0.976). Pirfenidone at a dosage of 50 mg x kg(-1) x d(-1) inhibited protein expression of TGF-beta1 and TIMP-1 in lung tissue in the early phase (0.79 and 0.75 times of control group), but had no effect on expression of MMP-13.
  
  
  CONCLUSIONS
  Low dose pirfenidone, especially at dosage of 50 mg x kg(-1) x d(-1), has significant anti-fibrotic effects on bleomycin-induced rat pulmonary fibrosis. Pirfenidone partially inhibits the enhancement of the expression of TGF-beta 1 and TIMP-1 in lung tissue.
authors.affiliation: Department of Respiratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730.
authors.forename: Xin-lun
authors.initials: XL
authors.lastname: Tian
authors.forename: Wei
authors.initials: W
authors.lastname: Yao
authors.forename: Zi-jian
authors.initials: ZJ
authors.lastname: Guo
authors.forename: Li
authors.initials: L
authors.lastname: Gu
authors.forename: Yuan-jue
authors.initials: YJ
authors.lastname: Zhu
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology; D001761:Bleomycin; D004305:Dose-Response Relationship, Drug; D006909:Hydroxyproline / Q000378:metabolism; D008168:Lung / Q000378:metabolism* / Q000473:pathology; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D011728:Pyridones / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D011728:Pyridones; D019715:Tissue Inhibitor of Metalloproteinase-1; D053773:Transforming Growth Factor beta1; D001761:Bleomycin; C093844:pirfenidone; D053509:Matrix Metalloproteinase 13; D006909:Hydroxyproline