Expression of TGF-beta 1, PDGF and IGF-1 mRNA in lung of bleomycin-A5-induced pulmonary fibrosis in rats.
OBJECTIVE
To investigate the influence of alveolar macrophages (AMs), fibroblasts and interstitial cells on development of lung fibrosis, and the interactions among TGF-beta 1 PDGF and IGF-1 and these cytokines-effects on lung fibrosis.


METHODS
Expressions of TGF-beta 1, PDGF and IGF-1 mRNA in the lung cells and lung tissues in different stages of Bleomycin-A5-induced pulmonary fibrosis in rats were studied through Northern hybridization.


RESULTS
The expressions of TGF-beta 1 and PDGF mRNA reached their peaks in AMs of pulmonary fibrosis in rats on the 7th day after Bleomycin-A5 instillation. It was similar with that in the lung tissues. IGF-1 mRNA remained relatively stable in AMs during the course. PDGF and IGF-1 mRNA increased gradually in fibroblasts, and reached the highest expressions in the interstitial cells. There was almost no TGF-beta 1 mRNA expression in all groups of fibroblasts.


CONCLUSIONS
AMs are the main sources of TGF-beta 1 and PDGF in the lung tissues with fibrosis induced by Bleomycin-A5 AMs are activated in the first weekend and secrete TGF-beta 1 and PDGF to promote fibroblasts proliferation and fibrosis. As fibrosis developed, fibroblasts have established PDGF and IGF-1 autocrine and these three cytokines paracrine nets combined with the interstitial cells to promote lung fibrosis.
Li
H
H
Department of Respiratory Medicine, First Affiliated Hospital of Beijing Medical University.
He
B
B
Que
C
C
Weng
B
B
D000818:Animals; D001761:Bleomycin / Q000031:analogs & derivatives; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008168:Lung / Q000378:metabolism*; D008297:Male; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D001761:Bleomycin; C025703:bleomycetin; D007334:Insulin-Like Growth Factor I