Fibroblasts were seeded in a 6-well plate at a density of 2 × 105 cells and then cultured for 24 h until the cells reached about 80%–90% confluence. Then, the siRNA mixture was prepared for further experiments. SCF-targeted pooled siRNA supplied by Dharmacon (GE Dharmacon, Lafayette, CO, USA) was diluted to 25 nM in 100 µL per well of serum-free DMEM and 20 µL per well transfection reagent was added into the diluted siRNA solution. After mixing and incubation for 20 min, 100 µL of the mixture was added to each well and incubated for 3 days at 37 °C under 5% CO2. The control group was fibroblasts transfected reagent without siRNA. The transgene expression efficiency was detected by qPCR. The siRNA sequences used in the experiment are shown in Table 1.