Early phase collagen synthesis in lungs of rats exposed to bleomycin

✍ Scribed by Brent E Van Hoozen; Katharine L Grimmer; Gregory P Marelich; Lucas C Armstrong; Jerold A Last

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 446 KB
• Volume: 147
• Category: Article
• ISSN: 0300-483X
• DOI: 10.1016/s0300-483x(00)00142-6

✦ Synopsis

Skin wound healing exhibits type III collagen synthesis occurring transiently as early as 10 h after injury, with subsequent synthesis of type I to form a scar. We hypothesized that similar collagen type switching also occurred in the bleomycin model of lung fibrosis in the rat. We could measure elevated lung collagen synthesis rates as early as 4 days after administration of bleomycin. Collagen type I:III ratios in whole lung remained constant for the first 7 days at the control level of 2:1, then increased to as high as 5:1 at day 21. Procollagen mRNA content, expressed as a ratio of type I:III mRNAs, was consistent with the protein synthesis data and the observed ratio of collagen types being made by the lungs at the various time points evaluated. We conclude that a transient increase in type III relative to type I collagen does not occur in the bleomycin rat lung model. Therefore, the sequence of type-specific collagen expression and deposition in the skin wound healing model is not entirely analogous to this widely used animal model of pulmonary fibrosis.