Temporal and spatial expression of biglycan in chronic oxygen-induced lung injury.
To assess the temporal and spatial expression of the matrix-associated proteoglycan, biglycan, in a model of chronic hyperoxia-induced lung injury, changes in mRNA and protein were examined using Northern blot analyses and immunohistochemistry. Newborn rats were exposed to 85% or 100% oxygen for 6 and 4 wk, respectively. Exposure to 85% oxygen for up to 6 wk resulted in a reduction in lung surface area and the development of focal areas of fibrosis. In contrast, exposure to 100% oxygen resulted in gross alterations in lung histology with greatly enlarged airspaces and septal thickening. Biglycan mRNA increased at 3 to 5 wk in control animals, then returned to baseline, while oxygen-exposed animals showed a further increase after 2 to 4 wk of exposure. Immunoreactive biglycan decreased with postnatal age but increased in alveolar cells of animals exposed to 100% oxygen for 4 wk and in alveolar cells and along alveolar septae of animals exposed to 85% oxygen for 6 wk. We speculate that biglycan binds growth factors such as transforming growth factor-beta near these cells, acting in an autoregulatory fashion to support epithelial cell proliferation and inhibit mesenchymal cell proliferation.
Veness-Meehan
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Department of Pediatrics, University of North Carolina at Chapel Hill 27599-7596.
Rhodes
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Stiles
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D000818:Animals; D000831:Animals, Newborn; D058578:Biglycan; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D016326:Extracellular Matrix Proteins; D018496:Hyperoxia / Q000378:metabolism*; D008168:Lung / Q000378:metabolism; D011509:Proteoglycans / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D011650:Pulmonary Alveoli / Q000378:metabolism / Q000473:pathology; D011658:Pulmonary Fibrosis / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014132:Trachea / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
D058578:Biglycan; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D012333:RNA, Messenger