OCLN and infection: The data show that after 2 h post-infection, the expression levels of ZO-1 and Occludin were not significantly different among NC, PC and EXP groups (P > 0.05) (Figures 3F,G); but after 6 h post-infection, the expression of ZO-1 was significantly decreased in the PC group compared to the EXP group (P < 0.05), and there was no significant difference between the NC and EXP groups (P > 0.05) (Figure 3F).