Vascular endothelial growth factor gene expression in ovine placenta and fetal membranes.
OBJECTIVE
The purpose of this study was to explore the gene expression of vascular endothelial growth factor (VEGF) in placental cotyledon, chorion, and amnion of the ovine fetus.


METHODS
Time-dated pregnant sheep with singleton or twin fetuses at a gestational age ranging from 100 to 140 days were used for the study. Placental cotyledonary, chorionic, and amniotic tissues were collected and processed for messenger ribonucleic acid analysis by Northern blotting and reverse transcription-polymerase chain reaction.


RESULTS
By use of a phosphorus 32-labeled human VEGF complementary deoxyribonucleic acid probe, a prominent VEGF messenger ribonucleic acid transcript of 3.7 kb was detected in the cotyledon, chorion, and amnion. A minor band of 1.7 kb was also found but only in the cotyledon and chorion. The abundance of messenger ribonucleic acid encoding VEGF was highest (p < 0.001) in the cotyledon and lowest in the amnion. In these tissues polymerase chain reaction-amplified products corresponding to VEGF121, VEGF165, VEGF189, and VEGF206 were identified by ethidium bromide. In addition, a polymerase chain reaction fragment corresponding to VEGF145 was observed. These fragments produced specific hybridization signals with the human VEGF radioactive probe where the intensity of the signal was strongest for VEGF165 and weakest for VEGF189.


CONCLUSIONS
VEGF gene expression was detected in the cotyledon, chorion, and amnion of the near-term ovine fetus. These findings suggest that vascular endothelial growth factor may play a role in the induction of angiogenesis and promotion of permeability in the microvessels that perfuse the placental and fetal membranes.
Cheung
C Y
CY
Department of Reproductive Medicine, University of California, San Diego, La Jolla 92093-0802, USA.
Singh
M
M
Ebaugh
M J
MJ
Brace
R A
RA
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D015342:DNA Probes; D016228:Endothelial Growth Factors / Q000235:genetics*; D005321:Extraembryonic Membranes / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D006801:Humans; D008222:Lymphokines / Q000235:genetics*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010761:Phosphorus Radioisotopes; D010920:Placenta / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase; D012756:Sheep; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D015342:DNA Probes; D016228:Endothelial Growth Factors; D008222:Lymphokines; D010761:Phosphorus Radioisotopes; D012333:RNA, Messenger; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D012194:RNA-Directed DNA Polymerase