title: Enhanced expression of mRNA for insulin-like growth factor-1 in post-burn hypertrophic scar tissue and its fibrogenic role by dermal fibroblasts.
abstract: Hypertrophic scarring (HSc) which frequently develops in patients following severe thermal injury is characterized by accumulation of extracellular matrix (ECM) proteins including type I and type III collagen. In this study, we examined the presence and quantity of IGF-1 mRNA transcripts in post-burn HSc. The results of dot blot experiments showed a 77.5% (100 +/- 8.15 vs 177.5 +/- 19, p < 0.01) increase in expression of IGF-1 IIIRNA in HSc tissue relative to normal dermis obtained from the same patients. A Northern blot analysis confirmed the specificity of the IGF-1 cDNA. This cDNA visualized four different transcripts with apparent sizes of 7.0, 3.9, 1.8 and 1.0 kb, similar to those previously reported. The possible fibrogenic role of IGF-1 was examined by analyzing the effect of this growth factor on the expression of mRNA for the pro alpha 1(I) chain of type I procollagen and the pro alpha 1(III) chain of type III procollagen in dermal fibroblasts. IGF-1 increased the expression of these transcripts as early as 6 h and the effect was maximal at 24 h. Quantitative analysis by densitometry showed a 149 and 166% increase in pro alpha 1(I) and pro alpha 1(III) mRNA after 24 h of IGF-1 treatment, respectively. This effect seems to be specific as the abundance of mRNA for the pro alpha 2(I) chain of type I procollagen or TIMP-II was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000328:Adult; D002056:Burns / Q000150:complications*; D017439:Cicatrix, Hypertrophic / Q000378:metabolism*; D003094:Collagen / Q000096:biosynthesis; D018076:DNA, Complementary / Q000235:genetics; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism*; D005355:Fibrosis; D005786:Gene Expression Regulation; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012867:Skin / Q000378:metabolism / Q000473:pathology*; D014945:Wound Healing
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D003094:Collagen