Objective:To evaluate the effects of mitomycin on the growth of human dermal fibroblast and immortalized human keratinocyte line (HaCat cell),particularly the effect of mitomycin on intracellular messenger RNA (mRNA) synthesis of collagen and growth factors of fibroblast.Methods:The normal dermal fibroblast and HaCat cell were cultured in vitro.Cell cultures were exposed to 0.4 and 0.04 mg/ml of mitomycin solution,and serum-free culture medium was used as control.The cellular morphology change,growth characteristics,cell proliferation,and apoptosis were observed at different intervals.For the fibroblasts,the mRNA expression changes of transforming growth factor (TGF)-β1,basic fibroblast growth factor (bFGF),procollagen Ⅰ,and Ⅲ were detected by reverse transcription polymerase chain reaction (RT-PCR).Results:The cultured normal human skin fibroblast and HaCat cell grew exponentially.A 5-min exposure to mitomycin at either 0.4 or 0.04 mg/ml caused marked dose-dependent cell proliferation inhibition on both fibroblasts and HaCat cells.Cell morphology changed,cell density decreased,and the growth curves were without an exponential phase.The fibroblast proliferated on the 5th day after the 5-min exposure of mitomycin at 0.04 mg/ml.Meanwhile,5-min application of mitomycin at either 0.04 or 0.4 mg/ml induced fibroblast apoptosis but not necrosis.The apoptosis rate of the fibroblast increased with a higher concentration of mytomycin (p<0.05).A 5-min exposure to mitomycin at 0.4 mg/ml resulted in a marked decrease in the mRNA production of TGF-β1,procollagen Ⅰ and Ⅲ,and a marked increase in the mRNA production of bFGF.Conclusions:Mitomycin can inhibit fibroblast proliferation,induce fibroblast apoptosis,and regulate intracellular protein expression on mRNA levels.In additon,mitomycin can inhibit HaCat cell proliferation,so epithelial cell needs more protecting to avoid mitomycin’s side effect when it is applied clinically. Objective: To evaluate the effects of mitomycin on the growth of human dermal fibroblast and immortalized human keratinocyte line (HaCat cells), particularly the effect of mitomycin on intracellular messenger RNA (mRNA) synthesis of collagen and growth factors of fibroblast. Methods: The normal dermal fibroblast and HaCat cells were cultured in vitro. Cell cultures were exposed to 0.4 and 0.04 mg / ml of mitomycin solution, and serum-free culture medium was used as control. cellular morphology change, growth characteristics, cell proliferation, and apoptosis were observed at different intervals. For the fibroblasts, the mRNA expression changes of transforming growth factor (TGF) -β1, basic fibroblast growth factor (bFGF), procollagen I, and III were detected by reverse transcription polymerase chain reaction (RT-PCR). Results: The cultured normal human skin fibroblast and HaCat cell grew exponentially. A 5-min exposure to mitomycin at either 0.4 or 0.04 mg / ml caused marked dose-dependent cell prolifer ation inhibition on both fibroblasts and HaCat cells. Cell morphology changed, cell density decreased, and the growth curves were without an exponential phase. The fibroblast proliferated on the 5th day after the 5-min exposure of mitomycin at 0.04 mg / ml. 5-min application of mitomycin at either 0.04 or 0.4 mg / ml induced fibroblast apoptosis but not necrosis. The apoptosis rate of the fibroblast increased with higher concentration of mytomycin (p <0.05). A 5-min exposure to mitomycin at 0.4 mg / ml resulted in a marked decrease in the mRNA production of TGF-β1, procollagen I and III, and a marked increase in the mRNA production of bFGF. Conclusions: Mitomycin can inhibit fibroblast proliferation, induce fibroblast apoptosis, and regulate intracellular protein expression on mRNA levels. In addition, mitomycin can inhibit HaCat cell proliferation, so epithelial cell needs more protecting to avoid mitomycin’s side effect when it is applied clinically.