(A and B) Cell viability was determined by MTT assay after exposure to various concentrations of PFOS for 24 h and 48 h. (C) D3 mESCs was exposed to PFOS for 24 h, cell morphology was observed. Magnification, 100×. Cells were cultured with various concentrations of PFOS (0.2 µM, 2 µM, 20 µM, and 200 µM) or DMSO as control. (D) Effects of PFOS on alkaline phosphatase staining in mESCs. Cells were cultured with various concentrations of PFOS (0.2 µM, 2 µM, 20 µM, and 200 µM) or DMSO as control. Scale bar = 25 µm. Values of the experiment were represented as the percentages of cell viability compared with that of the control and expressed as means ± S.E. from five separate experiments in which treatments were performed in quadruplicate. *indicates significant difference when the values were compared to that of the control at p<0.05.