Figure 6.

QAE activates the nuclear factor erythroid-2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway in BV2 microglial cells. (a) H₂O₂ production. Cells were pretreated with QAE (25–100 μg/mL, 3 h), and further exposed to LPS (100 ng/mL, 12 h). After staining with H₂DCF-DA (10 μM, 0.5 h), dichlorofluorescein (DCF) fluorescence intensity was detected using an automated plate reader (n = 8). (b) Expression of antioxidant protein. Cells were treated with QAE (50, 100 μg/mL) for 8 h. Equal loading of each protein was verified by β-actin immunoblotting (n = 4). (c) Heme oxygenase-1 (HO-1) (HOMX1) mRNA level. Cells were treated with QAE (50–200 μg/mL) for 7 h. Relative mRNA expression of HO-1 was normalized by expression of GAPDH (n = 4). (d) Phosphorylation of Nrf2. Cells were treated with 100 μg/mL of QAE for the indicated time (left), or 50, 100 μg/mL of QAE for 3 h (right) (n = 4). (e) Expression of Nrf2 in the cytoplasm and nuclear. Expressions of Nrf2 were normalized by β-actin (cytosolic) or TBP (nuclear) immunoblotting (n = 4). Significant versus control, * p < 0.05, ** p < 0.01, *** p < 0.001; Significant versus LPS alone-treated group, ^### p < 0.001.