Low-dose mifepristone increased angiogenesis in a manner involving AQP1.

Purpose: To investigate the molecular mechanisms governing aquaporin-1 (AQP1)-mediated, mifepristone-induced angiogenesis and improve the understanding of low-dose mifepristone serving as an anti-implantation contraceptive drug.

Methods: Human umbilical vein endothelial cells (HUVECs) were used to explore the effects of different concentrations of mifepristone (0, 65, and 200 nmol/L) on the activity of angiogenesis. Forty-five pregnant mice during the "window of implantation" were treated with different concentrations of mifepristone. HUVECs' proliferation was examined using a methyl thiazolyl tetrazolium (MTT) assay. The microvessel density (MVD) and the expression of AQP1 in endometrium were determined with immunohistochemical methods.

Results: The MVD and the expression of AQP1 were significantly higher than controls. Mifepristone at 200 nmol/L significantly affected HUVECs' proliferation during culture over 12 h, and pretreatment with AQP1-specific siRNA significantly inhibited the mifepristone-enhanced cell proliferation.

Conclusions: Low-dose mifepristone increased angiogenesis in a manner involving AQP1. This affords a new insight into the molecular mechanism underpinning the angiogenic effects of low-dose mifepristone.