Enhanced expression of mRNA for transforming growth factor-beta, type I and type III procollagen in human post-burn hypertrophic scar tissues.

To explore the possible role of locally synthesized transforming growth factor beta-1 (TGF-beta 1) and procollagen gene expression in postburn hypertrophic scars, we have compared mRNA levels for type I and type III procollagen and TGF-beta 1 in human hypertrophic scar tissue with normal dermis obtained from the same patients as a control. Northern blot analysis of total RNA extracted from hypertrophic scar tissue and normal skin demonstrated two transcripts for the pro-alpha 1(I) chain (5.8 kb and 4.8 kb) and for the pro-alpha 1(III) chain (5.4 kb and 4.8 kb) and one transcript (4.9 kb) for TGF-beta 1. Quantitative analysis of dot blot autoradiograms of mRNA from three samples of hypertrophic scar tissue and normal skin showed average increases of 102% (p < 0.05) for pro-alpha 1(I), 91% (p < 0.06) for pro-alpha 1(III), and 61% (p < 0.05) for TGF-beta 1. Three additional hypertrophic scar samples were quantitatively analyzed on Northern blots and showed increases of 246%, 102%, and 250% of the specific messages for pro-alpha 1(I), pro-alpha 1(III), and TGF-beta 1 relative to a normal skin control. Two transcripts (4.9 kb and 2.5 kb) for TGF-beta 1 were identified in cultured fibroblasts. In contrast to the results from tissue, the level of these transcripts in fibroblasts cultured from hypertrophic scar tissue and normal skin were not significantly different, suggesting that the synthesis of this growth factor is stimulated in tissue by a presently unknown mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)