Figure 3. Protective effects of paeoniflorin (PF) on H₂O₂-induced differentiated ARPE-19 cells. A: Levels of retinal pigment epithelium 65 (RPE65) and fibroblast growth factor receptor-1 (FGFR-1) mRNA were measured by Reverse transcriptase PCR in undifferentiated (Undiff ARPE-19) and differentiated (Diff ARPE-19) ARPE-19 cells. Total RNA from undifferentiated or differentiated ARPE-19 cells was reverse transcribed and amplified using primers for RPE65 and FGFR1. A reaction omitting the cDNA was used as a negative control (NC). B: Cell viability of differentiated ARPE-19 cells following H₂O₂ exposure were measured by MTT assay. The cells were treated with or without different concentrations of H₂O₂ (100–2,000 μM) for 24 h. Cell viability was measured by an MTT assay. The results are expressed as percentage of control, and each value represents the mean±SEM of three independent experiments (n=3 experiments, *p<0.05). C: Cell viability was measured in differentiated ARPE-19 cells treated with 1,200 μM H₂O₂ or different concentrations of PF (50–200 μg/ml) by an MTT assay. The results are expressed as percentage of control, and each value represents the mean±SEM of three independent experiments (n=3 experiments, *p<0.05).