Abstract: Objective To analyze the inhibitory effect of recombinant human endostatin(rhEndostatin) on human keloid-derived fibroblasts(KFs) in vitro.Methods The human’s KFs were cultured and identified in vitro. KFs were incubated with various concentrations of rhEndostatin solution(6.25×10-6, 1.25×10-5, 2.50×10-5, 5.00×10-5, 1.00×10-4mg/L).With the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenny- BR>lterazolium bromide(MTT) colorimetric assay the effects of rhEndostatin on the proliferation of cultured KFs were studied,and morphological changes of the KFs were also observed at different time points(24, 48, 72 hours). Results KFs from the keloid tissue started to appear on days 7-8 after it were planted, the number of the cells gradually increased and the growth of the cells showed a radial patten centred at the tissue-centric. Second subculture KFs had a single-layer arrangement, were uniform, showed long fusiform, and had good refractive index.Mouse anti-Vimentin was positive.Buffy positive reaction product was observed in the cytoplasm. Cells growth inhibition occurred at 1.25×10-5mg/L or higher concentration in a dose-dependent manner and maximum inhibition occurred at 48 hours. After incubation with rhEndostatin(5.00×10-5mg/L and 1.00×10-4 mg/L) for 48 hours ,observation under the microscope showed the cells slowed growth,

Key words: Endostatin, Keloid, Fibroblasts, Proliferation, MTT