Fig. 5. Effect of TBP and TBEP on the MAPK protein expression. (A) HepG2 cells were treated with different concentrations of TBP and TBEP (50, 100, and 200 μM) for 24 h. The expressions of MAPK pathway proteins were measured by using the western blot assay, and the GAPDH protein expression was used as the internal reference. (B) Quantization of the expression of proteins. (C) Control groups. HepG2 cells without OPFR treatment. *p < 0.05, **p < 0.01 compared with the control (C) groups.