Short courses of low dose dexamethasone delay bleomycin-induced lung fibrosis in rats.
After comparing mortality and clinical signs in rats receiving different dexamethasone treatments, we investigated whether 0.5 mg/kg/d dexamethasone could delay pulmonary fibrosis induced by bleomycin and its time course (1, 3, 7, 14, 21 and 28 days). Tissue injury was assessed by apoptosis, lactate dehydrogenase (LDH) release, malondialdehyde content, and protein content; and inflammation was measured in terms of myeloperoxidase (MPO) activity, inflammatory cell count, and the mRNA expression of pro/inflammatory cytokines. Fibrogenic activity was analyzed by measuring the mRNA expression of fibrotic cytokines in tissue, and the promotion of fibroproliferation and synthesis of collagen type I by bronchoalveolar lavage fluids in vitro; and fibrosis was assessed by measuring the hydroxyproline content and collagen-I mRNA expression, and by histology. Bleomycin treatment induced tissue injury, inflammation and fibrogenic activity in lung, and led to fibrosis. Treatment with dexamethasone diminished the extent of fibrosis by strongly reducing inflammation, lung damage, and fibrogenic activity. These results demonstrate that the progression of bleomycin-induced pulmonary fibrosis in rats can be delayed by dexamethasone treatment, which appeared to alleviate not only inflammation but also lung damage and fibrogenic activity, indicating a possible new role for dexamethasone in the treatment of fibrosis.
Fangping
F
Chen
Likun
L
Gong
Ling
L
Zhang
Hui
H
Wang
Xinming
X
Qi
Xiongfei
X
Wu
Ying
Y
Xiao
Yan
Y
Cai
Linlin
L
Liu
Xianghong
X
Li
J
J
Ren
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001761:Bleomycin; D001835:Body Weight / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000187:drug effects / Q000473:pathology; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000401:mortality / Q000517:prevention & control*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015996:Survival Rate; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects
D000893:Anti-Inflammatory Agents; D024042:Collagen Type I; D016207:Cytokines; D001761:Bleomycin; D008315:Malondialdehyde; D003907:Dexamethasone; D007770:L-Lactate Dehydrogenase