Firstly, we detected the expression of MMP7, COX2, and PAI-1 genes after infection of H. parasuis, as shown in Figures 7A,B, real-time RT-PCR showed SH0165 infection but not HN0001 led to a significant upregulation of expression of all three genes in PK-15 cells (Figure 7A) and only expression of COX2 and PAI-1 in NPTr cells (Figure 7B) compared to uninfected cells. This evidence concerns the gene SERPINE1 and infection.