Objective: To explore the pathophysiology of oligohydramnios, the association between the expression of aquaporin 1 and aquaporin 3 in fetal membranes and placenta and oligohydramnios was investigated.
Methods: Sixty patients underwent elective cesarean sections at term were studied, 30 patients with isolated oligohydramnios and the other 30 with normal amniotic fluid volume (AFV). Real-time polymerase chain reaction and immunohistochemistry were employed to determine expression and localization of aquaporin 1 and aquaporin 3 in amnion, chorion and placenta, respectively.
Results: The expression of aquaporin 1 and aquaporin 3 was detected in amnion, chorion and placenta using real-time RT-PCR. By immunohistochemistry, aquaporin 1 and aquaporin 3 protein expressions in amnion epithelia and chorion cytotrophoblasts were identified. In placenta, aquaporin 1 was detected in placental vessels, while aquaporin 3 was found in trophoblast cells. In comparison to normal AFV group, there was a significant decrease of aquaporin 1 expression in amnion in oligohydramnios group, but no significant difference in chorion and placenta between the two groups. The expression of the aquaporin 3 in amnion and chorion in oligohydramnios group was significantly decreased, while expression in placenta was significantly increased compared with that in normal AFV group.
Conclusions: Alteration of aquaporin 1 and aquaporin 3 expression in fetal membranes and placenta may be important in the pathophysiology of isolated oligohydramnios.