Reduction of aquaporin-8 on fetal membranes under oligohydramnios in mice lacking prostaglandin F2 alpha receptor.
OBJECTIVE
To investigate the association between aquaporin-8 (AQP-8: a water channel protein) expression in fetal membranes and oligohydramnios during near-term and postdate pregnancy, we set up an oligohydramnios model using prostaglandin F2 alpha receptor (FP)-deficient mice.


METHODS
Pregnant FP-deficient mice from 14 to 21 gestational days (GD) were killed to measure the amniotic fluid volume (AFV), and fetal membranes were collected for the analysis of aquaporin-8 expression.


RESULTS
The AFV was highest at 14 GD, and was significantly decreased to 28% and 0% at 20 GD and 21 GD, respectively, compared with the volume at 14 GD. Immunohistochemistry and immunoblot analysis showed that aquaporin-8 was expressed in the basal component of fetal membranes, and that the protein level was significantly decreased to 60% at 20 GD compared with that at 14 GD.


CONCLUSIONS
We demonstrated that AQP-8 expression in the fetal membrane was decreased at post term in FP-deficient mice. Our findings suggest that aquaporin-8 in fetal membranes may be involved in the regulation of AFV, especially when oligohydramnios occurs.
Shioji
Mitsunori
M
Department of Obstetrics and Gynecology, Osaka University, Graduate School of Medicine, Osaka, Japan.
Fukuda
Hirotsugu
H
Kanzaki
Toru
T
Wasada
Kenshi
K
Kanagawa
Takeshi
T
Shimoya
Koichiro
K
Mu
Junwu
J
Sugimoto
Yukihiko
Y
Murata
Yuji
Y
D000653:Amniotic Fluid / Q000502:physiology; D000818:Animals; D020346:Aquaporins / Q000096:biosynthesis*; D005321:Extraembryonic Membranes / Q000378:metabolism*; D005260:Female; D051379:Mice; D018345:Mice, Knockout; D016104:Oligohydramnios / Q000378:metabolism*; D011247:Pregnancy; D011982:Receptors, Prostaglandin / Q000378:metabolism*
D020346:Aquaporins; D011982:Receptors, Prostaglandin; C108330:aquaporin 8; C034671:prostaglandin F2alpha receptor