Figure 4: Effect of RA on ROS production. UM-SCC-6 (A) and UM-SCC-10B (B) cells were treated with RA at concentrations ranging from 10 μg/ml to 80 μg/ml for 24 hrs, followed by incubation with CM-H2DCFDA for 30 mins. ROS production was determined by measuring fluorescence at excitation 485/20 and emission at 528/20. Data are expressed mean ± SD (n=5). *p<0.05, **p<0.01, ***p<0.0001 vs control.