Six placenta permeability-related genes: molecular characterization and expression analysis in pigs

The nutrient transportation ability of placenta depends on placental size, vascular density and permeability. Regulation of angiogenesis in the placenta is critical for successful gestation. Placenta vascularity exhibits disparity in different gestation stages and different pig breeds. To investigate the expression of genes related to permeability in the porcine placenta of different gestation stages and breeds, molecular cloning and gene expression analysis of six porcine genes, vascular endothelial growth factor (VEGF), VEGF-R1, VEGF-R2, endothelial nitric oxide synthase (eNOS), vascular endothelial cadherin (CDH5) and β-arrestin2 (Arrb2), were performed in this study. The results demonstrated that from gestation day 33 to day 90, Landrace exhibited significant increase (P < 0.05) in placental VEGF and Arrb2 mRNA expression. Moreover, expression levels of VEGF, VEGF-R1, VEGF-R2 and eNOS mRNA were higher (P < 0.01) in the placenta of Erhualian than those in Landrace on day 90 of gestation. In contrast, CDH5 placental mRNA expression level exhibited significant decrease (P < 0.05) from day 33 to day 90 gestation in Landrace. Erhualian placental CDH5 and Arrb2 expression levels were significantly lower (P < 0.01) than those in Landrace conceptuses on day 90 of gestation. Our study offered new data on the expression of genes in VEGF signal transduction pathway in porcine placenta.