Fig. 4

Autophagy-mediated oxidative stress influences the yield of H9N2 influenza virus. Following transfection with control siRNA or Atg5 siRNA, A549 cells were infected with the H9N2 influenza virus. (a) Following incubation for 24 h, the cells were treated with NAC (10 mM) or H₂O₂ (0.1 mM) for 6 h, supernatants were collected, and the viral titer was determined by measuring TCID₅₀. (b) ROS generation, (c) MDA contents, and (d) SOD1 activity were measured in the cells. (e, f) A549 cells were also treated with Atg5 siRNA or LY294002, and NP mRNA was detected by RT-PCR. The data are presented as the means ± SD (n = 5). **P < 0.01