Tanshinone IIA increased amniotic fluid volume through down-regulating placental AQPs expression via inhibiting the activity of GSK-3β.

The mechanism of idiopathic oligohydramnios is still uncertain, and there is no effective and targeted treatment for it. Placental aquaporins (AQPs) were associated with idiopathic oligohydramnios. This study aimed to investigate the effect of tanshinone IIA on amniotic fluid volume (AFV) and its underlying molecular mechanisms related to placental AQPs (AQP1, AQP3, AQP8, AQP9). Results showed that compared with the women with normal AFV, placental AQP1, AQP3, AQP8, and AQP9 protein expressions were decreased in women with idiopathic oligohydramnios. Immunohistochemistry revealed localization of AQP1, AQP3, AQP8, and AQP9 mainly in trophoblast cells within labyrinth zone of mouse placenta. Also, AQP1 was located in fetal vascular endothelial cells. Pregnant mice were administered with tanshinone IIA (10 mg/kg or 50 mg/kg, n = 8, respectively) or vehicle (n = 8) from 9.5 to 18.5 gestational day (GD). Tanshinone IIA markedly increased the AFV in pregnant mice, without the effects on embryo numbers per litter, atrophic embryo rate, fetal weight, and placental weight, as well as increased the expressions of AQPs and inhibited the activity of GSK-3β in mice placenta. In JEG-3 cells, tanshinone IIA downregulated AQP1, AQP3, AQP8, AQP9 expressions and inhibited the activity of GSK-3β. Activating GSK-3β with MK-2206 eliminated these alterations. Thus, tanshinone IIA could increase AFV in pregnant mice, possibly through downregulating placental AQP1, AQP3, AQP8, and AQP9 expression via inhibiting the activity of GSK-3β. Tanshinone IIA may be optional for the treatment of idiopathic oligohydramnios.