Placental and membrane aquaporin water channels: correlation with amniotic fluid volume and composition.
OBJECTIVE
To assess the role of aquaporins (AQPs) in the regulation of amniotic fluid (AF) volume, we determined AF volume and composition and placental and fetal membrane AQP expression throughout the second half of murine gestation.


METHODS
Pregnant CD1 mice were sacrificed at e10-19 and AF volume and composition determined. Placenta and fetal membranes were screened for AQP gene expression. AQP gene expression was quantified by real-time RT PCR and protein location determined by immunohistochemistry. Changes in AF volume were correlated with AQP expression.


RESULTS
Both membranes and placenta demonstrated expression of AQP1, -3, -8 and -9. Advancing gestation was associated with increased AF volume from e10 to e16, with a marked decrease in AF volume from e16 to e19. By immunohistochemistry, AQP1 was localized to placental vessels and AQP3 to trophoblast. AF volume was negatively correlated with fetal membrane AQP1 and placental AQP1 and AQP9 expression, and positively correlated with placental AQP3 expression.


CONCLUSIONS
Changes in AQPs with advancing gestation, and their correlation with AF volume, suggest a role in mediating placental and membrane water flow and ultimately AF volume. AQP1 appears to regulate fetal membrane water flow, and AQP3 is a likely candidate for the regulation of placental water flow.
Beall
M H
MH
Department of Obstetrics and Gynecology, Harbor-UCLA Medical Center, Los Angeles Biomedical Research Institute at Harbor-UCLA, Torrance, CA, USA. mub@ucla.edu <mub@ucla.edu>
Wang
S
S
Yang
B
B
Chaudhri
N
N
Amidi
F
F
Ross
M G
MG
D000653:Amniotic Fluid / Q000502:physiology*; D000818:Animals; D051398:Aquaporin 1 / Q000235:genetics; D051399:Aquaporin 2 / Q000235:genetics; D051400:Aquaporin 3 / Q000235:genetics; D020346:Aquaporins / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000502:physiology*; D017931:DNA Primers; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D007150:Immunohistochemistry; D051379:Mice; D010920:Placenta / Q000166:cytology / Q000502:physiology*; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction
C496021:Aqp1 protein, mouse; C496024:Aqp2 protein, mouse; C496028:Aqp3 protein, mouse; C491638:Aqp9 protein, mouse; D051399:Aquaporin 2; D020346:Aquaporins; D017931:DNA Primers; D051398:Aquaporin 1; D051400:Aquaporin 3