The Effect of Tumor Necrosis Factor-alpa on Type I Procollagen and Collagenase Gene Expression in Hypertrophic Scar and Keloid Fibroblast

ABSTRACT

Recent studies have demonstrated that tumor necrosis factor-alpa(TNF-alpa) decreased production of type I and III procollagens and increased production of collagenase in cultured human dermal fibroblasts. The purpose of this study was to examine the effect of TNF-alpa on the level of expression of type I procollagen, collagenase mRNA in hypertrophic scar and keloid fibroblasts in culture. The cultured fibroblasts from normal skin, hypertrophic scar and keloid were exposed to 0, 1, 10, and 100 ng/ml of TNF-alpa for 24 hours. Then, type I procollagen mRNA and collagenase mRNA were measured by quantitative RT-PCR and quantified by computerized densitometry(TINA). In normal skin fibroblasts, TNF-alpa significantly decreased the level of type I procollagen mRNA and increased collagenase mRNA. The maximal inhibition for type I procollagen mRNA was noted at 100 ng/ml of TNF-alpa and maximal enhancement for collagenase mRNA was noted at 100ng/ml of TNF-alpa. In hypertrophic scar fibroblasts, TNF-alpa significantly decreased the level of type I procollagen mRNA and increased collagenase mRNA. The maximal inhibition for type I procollagen mRNA was noted at 100 ng/ml of TNF-alpa which was the same as normal skin fibroblasts but there were no significant differences among TNF-alpa treated groups for collagenase mRNA. In keloid fibroblasts, TNF-alpa also significantly decreased the level of type I procollagen mRNA and increased collagenase mRNA. The maximal inhibition for type I procollagen mRNA was noted at 100 ng/ml of TNF-alpa which was the same as normal skin and hypertrophic scar fibroblasts but there were no significant differences among TNF-alpa treated groups for collagenase mRNA. These results strongly suggested that TNF-alpa might have a role in preventing progression of fibroproliferative disease, such as hypertrophic scar or keloid, and that the most effective concentration of TNF-alpa was found in 100 ng/ml.