Effects of siRNA on C6/36 cell survival rate. C6/36 cells were transfected with DenSi-1(B) or control siRNA(C), and challenged by DEN-1(B-D). CPEs were observed and cell survival rates were measured by MTT assay at the 7th dpi. Compared with virus positive control group, the cell survival rate of siRNA group increased by 2.26-fold (n = 5, P < 0.05), but siRNA control group showed no significant difference (n = 5, P > 0.05) A: normal control group; B: siRNA treatment group; C: siRNA control group; D: virus positive control group; Up: CPEs of C6/36 cells at the 7th dpi; Down: MTT assay results for C6/36 cells survival rate at the 7th dpi (n = 5). * P < 0.05, compared with virus positive control group.