OBJECTIVE:To investigate the effects of a modified Dahuang Zhechong Pill (MDZP) on the angiogenesis of rhesus choroid-retina endothelial (RF/6A)cells and its preliminary mechanism.METHODS:A 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) method was used to assess the effect of a MDZP on RF/6A cell proliferation induced by vascular endothelial growth factor (VEGF).Transwell inserts were used to assess the effect of the MDZP on RF/6A cell migration.Matrigel was used to assess the effect of the MDZP on the tube formation of RF/6A cells.West blotting and quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) were used to detect the protein and mRNA expression,respectively,of VEGF and matrix metalloproteinase-2 (MMP-2) in RF/6A cells treated with the MDZP.RESULTS:RF/6A cell proliferation induced by VEGF was inhibited by 0.2 mg/mL MDZP.At 0,12.5,25 and 50 mg/mL MDZP,the number of cells that migrated through Transwell membranes was 73.33±4.51,61.33±4.04,28.67±6.66 and 17.67±4.16,respectively,and the number of tubes formed in Matrigel was 20.33 ± 0.58,13.33 ± 1.53,11.00 ± 1.00 and 1.33±0.58,respectively.At 100 and 200 mg/mL MDZP,the protein and mRNA expression of VEGF and MMP-2 were inhibited in RF/6A cells.At 400 mg/mL MDZP,the expression of VEGF mRNA and MMP-2 protein were inhibited in RF/6A cells.CONCLUSIONS:MDZP inhibits the angiogenesis of RF/6A cells via the suppression of proliferation,migration and tube formation of RF/6A cells.Inhibition of the protein and mRNA expression of VEGF and MMP-2 in RF/6A cells may be an important mechanism.