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Medline ® Abstract for Reference 54

of 'Physiology of amniotic fluid volume regulation'

Reduction of aquaporin-8 on fetal membranes under oligohydramnios in mice lacking prostaglandin F2 alpha receptor.
Shioji M, Fukuda H, Kanzaki T, Wasada K, Kanagawa T, Shimoya K, Mu J, Sugimoto Y, Murata Y
J Obstet Gynaecol Res. 2006;32(4):373.
AIM: 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 wasdecreased 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.
Department of Obstetrics and Gynecology, Osaka University, Graduate School of Medicine, Osaka, Japan.