Fig. 6

Effects of PQQ on levels of ROS and ROS-regulated proteins in cells treated with siRNA. a Level of ROS in IPEC-J2 cells treated with or without Nrf2 siRNA-2. b-c Ratio of Bcl-2/Bax mRNA levels and mRNA expression levels of Caspase-3 in IPEC-J2 cells treated with or without Nrf2 siRNA-2. d Western blot analysis of cytoplasmic Bax, Bcl-2 and Caspase-3. Densitometric values were normalized to those of β-actin. e Statistical analysis of the data in D. f Statistical analysis of the Bcl-2/Bax protein ratio. CTRL, cells cultured with basal medium; H₂O₂, cells cultured with 200 μmol/L H₂O₂ for 2 h; PQQ, cells cultured with 10 nmol/L PQQ for 6 h and then incubated with both H₂O₂ (200 μmol/L) and PQQ (10 nmol/L) for another 2 h. NC siRNA, cells transfected with NC siRNA and then pretreated with PQQ for 6 h prior to incubation with both PQQ and H₂O₂ for another 2 h. Nrf2 siRNA, cells transfected with Nrf2 siRNA-2, pretreated with PQQ for 6 h, and then incubated with both PQQ and H₂O₂ for another 2 h. n = 3