Figure 2. SP improves viability of RPE cells damaged due to oxidative stress. A: Experimental scheme for oxidative stress, substance P (SP), or CP-96345 treatment. B: Cell morphology was observed. Scale bar: 100 μm. C: Cell viability was measured with the thiazolyl blue tetrazolium bromide (MTT) assay. The untreated control was set as 100%, and cell viability was expressed as a percentage relative to the activity of the control group. P values of less than 0.05 were considered statistically significant (*p<0.05, **p<0.01, ***p<0.001). The data are expressed as the mean ± standard deviation (SD) of three independent experiments.