Autophagy inhibition decreases oxidative stress-promoted PCV2 replication. PK15 cells were infected with PCV2 at MOI of 1, cells were pretreated with 3-MA (5 mM) or transfected with the siATG5 and then cultured with different concentrations of H2O2 for 48 h. A–D The expression of ATG5 and LC3-II protein was detected by Western blotting. E Cells were transfected with GFP-LC3 plasmid and analyzed by fluorescence microscopy for the presence of fluorescent GFP-LC3 puncta. Scale bar: 10 μm. F, G The number of infected cells was detected by immunofluorescence assay. H Real-time PCR was used to detect the PCV2 viral DNA copies. All results are presented as mean ± SEM (n = 3, each). Significance compared with PCV2-infected and H2O2 treatment group (*P < 0.05 and **P < 0.01).