title: Expression of the vascular endothelial growth factor-receptor system in the porcine endometrium throughout the estrous cycle and early pregnancy.
abstract: The objective of this study was to investigate the protein and mRNA expression of vascular endothelial growth factor (VEGF), VEGFR-1 (fms-like tyrosine kinase, Flt-1) and VEGFR-2 (fetal liver kinase-1/kinase insert domain-containing receptor, Flk-1/KDR) in the endometrium during the estrous cycle and early pregnancy in pigs. The VEGF-receptor system was localized in epithelial and stromal cells, blood vessels, and myometrium. Western blot analysis showed higher levels of VEGF protein during the periovulatory and periimplantation periods (P < 0.001, and P < 0.05, respectively). Constant expression of VEGF mRNA during the cycle and significant upregulation on Days 22-25 of gestation (vs. Days 9-17; P < 0.001) was observed. Stable levels of VEGFR-1 mRNA and protein were detected in the endometrium of cyclic animals. However, higher VEGFR-1 protein expression was found on Days 16-17 of the estrous cycle (P < 0.01) and Days 13-15 of gestation (P < 0.05). Protein expression of VEGFR-2 was elevated on Days 2-4 of the estrous cycle (P < 0.001), but mRNA levels were constant during the cycle. In pregnancy, VEGFR-2 protein expression started to increase after Day 15 (vs. Days 9-12; P < 0.05), but induction of VEGFR-2 mRNA expression occurred earlier on Days 13-15. It appears from the present study that the VEGF-receptor system is regulated in a temporal and spatial manner during the estrous cycle and early pregnancy in pigs. The results suggest that VEGF-A family members are probably involved in appropriate preparation of endometrium for implantation and in vascular events during implantation in pigs.
authors.affiliation: Division of Reproductive Endocrinology and Pathophysiology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland. moka@pan.olsztyn.pl
authors.forename: Monika M
authors.initials: MM
authors.lastname: Kaczmarek
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Waclawik
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Blitek
authors.forename: Anna E
authors.initials: AE
authors.lastname: Kowalczyk
authors.forename: Dieter
authors.initials: D
authors.lastname: Schams
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Ziecik
mesh_terms: D000199:Actins / Q000235:genetics; D000818:Animals; D004717:Endometrium / Q000502:physiology*; D066246:ErbB Receptors / Q000235:genetics*; D004971:Estrus / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation; D011247:Pregnancy; D011270:Pregnancy, Animal; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000235:genetics; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics
chemical_list: D000199:Actins; D012333:RNA, Messenger; D066246:ErbB Receptors; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2