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Background: A recent study found that Salvia miltiorrhiza extract substantially increased amniotic fluid index in women with oligohydramnios. Abnormal aquaporin (AQP) expression is associated with oligohydramnios. This study aims to investigate the effect of tanshinone IIA, the major lipophilic component in the root of Salvia miltiorrhiza, on the function and expression of AQPs in human amniotic epithelial WISH cells and the molecular mechanism underlying the effect., Methods: WISH cells were treated with tanshinone IIA. Cell proliferation and swelling were determined by cell counting kit-8 assay and measurement of cell size, respectively. A human phospho-MAPK antibody array was used to screen tanshinone IIA-associated signaling molecules. The protein expression of AQPs, glycogen synthase kinase 3β (GSK-3β), and phosphorylated GSK-3β (p-GSK-3β) was analyzed by Western blot., Result: Tanshinone IIA significantly inhibited WISH cell proliferation at ≥50μM (P<0.05) and the IC 50 was 35μM. Cell size was significantly increased by the treatment with 35μM tanshinone IIA for 24h (P<0.05). WISH cells expressed AQP1, AQP3, AQP8, and AQP9 predominantly in cytoplasm. The dose of tanshinone IIA to maximally induce AQP1 and AQP3 expression was 35μM; for AQP8 and AQP9, the dose of maximal stimulation was 5μM (All P<0.05). Tanshinone IIA (35μM)-mediated up-regulation of AQP8, AQP9, AQP1, and AQP3 peaked at 6, 12, 24, and 24hours of treatment, respectively. Tanshinone IIA increased p-GSK-3β level significantly (P<0.05). Blockade of GSK-3β expression by siRNA and inhibition of GSK-3β activity by lithium chloride significantly reduced tanshinone IIA-induced AQP1 and AQP3 expression (All P<0.05)., Conclusion: Tanshinone IIA increases AQPs expression in WISH cells by stimulating p-GSK-3β. AQP8 responds to tanshinone IIA the most rapidly compared with AQP9, AQP1, and AQP3 in WISH cells., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Previous studies by our group as well as other researchers have found expression of Aquaporins (AQPs) 1, 3, 8, and 9 in human chorioamniotic membranes and placenta. Our previous study found that the alteration of the expression of AQPs 1, 3, 8, and 9 in placenta and fetal membranes was an adaptive response to maintain amniotic fluid homeostasis in case of abnormal amniotic fluid volume, which is likely to affect the intramembranous absorption and transport of water and solute from mother to fetus. However, the actual regulation mechanisms of intramembranous absorption and placental water flow are not yet clear, making it difficult to treat abnormal amniotic fluid volume effectively. Several studies found that many factors, including hormone levels, osmotic pressure, temperature, and oxygen concentration, regulate expression of AQPs in placenta, fetal membranes, and other mammalian organs through several signal transduction pathways, such as the cAMP, the MAPK, the PI3K/AKT, and the PKC pathways. These factors could provide potential therapeutic targets for the treatment of abnormal amniotic fluid volume.