(A) Assessment of ROS levels by 2,7-dichlorodihydrofluorescein-diacetate (DCFH-DA) staining revealed that the percentage of fluorescent dichlorofluorescein (DCF)-positive hESCs was significantly decreased in the 2 and 4 mM NaF-treated groups, and the mean fluorescence intensities of hESCs were significantly lower in the 1, 2 and 4 mM NaF-treated groups. (B) The expression of the cellular antioxidant defense enzyme SOD and the oxidative stress genes PRDX5 and CYBA did not show significant changes after NaF treatment, except for NOS, whose expression was significantly decreased in the 2 and 4 mM NaF-treated hESCs. *, p < 0.05. **, p < 0.01. ***, p < 0.001.