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Document type:
Zeitschriftenaufsatz 
Author(s):
Kaczmarek, M.M.; Waclawik, A.; Blitek, A.; Kowalczyk, A.E.; Schams, D.; Ziecik, A.J 
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 RNA 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. 
Keywords:
angiogenesis; VEGF; VEGFR-1; VEGFR-2; endometrium; pig 
Journal title:
Molecular Reproduction and Development 
Year:
2008 
Journal volume:
75: 
Pages contribution:
362-372 
Language:
en 
Fulltext / DOI:
Accepted:
22.06.2007 
Date of publication:
14.09.2007 
TUM Institution:
Zentralinstitut für Ernährungs- und Lebensmittelforschung / Abteilung Physiologie 
Format:
Text