After successful infection in the BEAS-2B cells, the quantitative PCR results show that the VEGF gene expression in the OE group was 2.036 times that in the NC group (P = 0.000366182) (Figure 4F), and the MMP-9 gene expression in the OE group was 1.443 times that in the NC group (P = 0.035845639) (Figure 4G). Here, MMP9 is linked to infection.