Caffeic acid phenethyl ester up-regulates antioxidant levels in hepatic stellate cell line T6 via an Nrf2-mediated mitogen activated protein kinases pathway

Figure 5 Phosphorylation levels of ERK1/2, p38MARK, and JNK1/2 are significantly increased in a dose-dependent manner in hepatic stellate cell-T6 cells. A: Effect of caffeic acid phenethyl ester on phosphorylation of ERK1/2, p38MAPK and JNK. Western blot analysis of total and phosphorylated protein levels of ERK1/2, p38MARK and JNK in HSC-T6 cells treated with CAPE (5 μmol/L, 10 μmol/L and 15 μmol/L) was performed. Total MAPKs were used as the internal control. The gray levels were normalized against those of the corresponding total MAPKs and the results are expressed, relative to control; B: Effect of inhibitors of MAPKs on the expression of Nrf2 in HSC-T6 cells. Cells were treated with ERK1/2 inhibitor PD98059 (30 μmol/L), p38 MAPK inhibitor SB203580 (20 μmol/L) or JNK inhibitor SP600125 (25 μmol/L) for 2 h, then incubated with CAPE (15 μmol/L) for 24 h, and protein expression was evaluated by Western blot. Lane 1: Control group; Lane 2: 15 μmol/L CAPE group; Lane 3: CAPE + PD98059 group; Lane 4: CAPE + SB203580 group; Lane 5: CAPE + SP600125 group. Histone was used as the internal control to reflect the expression of nuclear Nrf2. The gray levels were normalized against histone and the results are expressed, relative to control. The data are the mean ± SD of three independent experiments. ^aP < 0.05 vs control; ^cP < 0.05 vs CAPE group. CAPE: Caffeic acid phenethyl ester.