The spots in the microarray were randomly selected and their expressions were confirmed by RT-PCR. Among genes with differential expressions, 3 genes were randomly selected and these genes and house keeping gene (GAPDH) were subjected to RT-PCR. The relative expressions were expressed as the expressions of target genes normalized by that of GAPDH (2 -△△ Ct ). Melting curve and 2 -△△ Ct method were used to compare the difference in the expressions between control group and PE group. Results from RT-PCR were consistent with microarray analysis.