Changes in type of collagen during the development of human post-burn hypertrophic scars.

Neutral-salt soluble collagen was relatively abundant in young post-burn hypertrophic scars. The content of insoluble collagen was fairly low in granulation tissues, whereas it gradually increased over 2 years and reached a significantly higher value than that in normal skins. Interrupted gel electrophoresis was carried out to estimate the relative proportions of type III and type I collagens in the pepsin digests of human normal skins and post-burn scars. Granulation tissues showed an abnormally higher ratio of type III to type I (0.37--0.72) than the mean value of normal skins (0.17 +/- 0.04 (S.D.)). The ratio gradually decreased to the normal range after 2 years or so.