Abstract: Objective To investigate the cause of excessive collagen accumulation in keloid tissue. Methods Human dermal fibroblasts were cultured from keloid and normaI skin.Collagen production by fi-broblasts in monolayer culture and in collagen gel was assessed by 3H-roline incorporation.Type I procollagen mRNA level of fibroblasts in monolayer culture was determined by dot blot hybridization using human proα(I)collagen-specific cDNA probe.Results The collagen synthesis significantly increased in keloid fibroblast lines (P<0.01), acompanied by a rise in type I procollagen-specific.mRNA levels in comparison with normal dermal fibroblast lines.Conclusion These findings suggest that the fihroblasts are activated in collagen syn-thesis in active keloid.The enhanced collagen synthesis by fibroblasts might contribute to excessive collagn ac-cumulation in keloid.

Key words: Keloid, Fibroblasts, Collagen