Effects of growth factors on mucosal scar fibroblasts in culture--a possible role of growth factors in scar formation.

Various growth factors are known to play important roles in wound healing, especially in an early inflammatory phase. However, their roles in subsequent scar formation phase are relatively unexplored. The aim of this study is to investigate the mechanisms of regulation in scar formation by these factors. Scar fibroblasts (SF) were obtained from immature scar tissue made at rat hard palate 1 month after excision and normal fibroblasts (NF) were obtained from the palatal mucosa of untreated control animals. SF showed a longer doubling time, and increased level of protein synthesis when compared to NF. Platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) stimulated [3H]-thymidine uptake less effectively in SF than in NF. In both cells, transforming growth factor-beta 1 (TGF-beta 1) inhibited EGF-induced stimulation of [3H]-thymidine uptake, but had no effects when it was added alone. TGF-beta 1 increased collagen synthesis more effectively in SF than in NF. These data indicate that the growth factors may play key roles in regulating proliferation and metabolic activity of fibroblasts during scar formation.