Objective Type B synoviocytes (fibroblast-Like synoviocytes)of rheumatoid arthritis are the proliferative cells in proliferative synovium. This study investigated if arsenic trioxide(As_2O_3) can reduce rheumatoid synoviocytes and change c-myc gene expression.Methods Type B synoviocytes of a patient with rheumatoid arthritis were separated and cultured. Synoviocytes were treated by 2μmol/L and 5μmol/L As_2O_3 medium for 24 h and 48 h. Death cells were analyzed by flow cytometry. Levels of c-myc protein were...