The effect of 17α-ethynylestradiol induced intrahepatic cholestasis of pregnancy on placental P-glycoprotein in mice: Implications in the individualized transplacental digoxin treatment for fetal heart failure.

INTRODUCTION

Placental P-glycoprotein (P-gp) plays a significant role in controlling transplacental digoxin transfer rate. Investigations on P-gp regulation in placenta of women with different pregnant pathological states are of great significance to individualized transplacental digoxin treatment for fetal heart failure (FHF). This study aimed to explore the effect of 17α-ethynylestradiol induced intrahepatic cholestasis of pregnancy (ICP) on placental P-gp in mice.

METHODS

ICP model in mice was induced by subcutaneous injection of 17α-ethynylestradiol dissolved in propylene glycol once daily from E12.5 to E16.5. Maternal plasma ALT, AST, TB, DBIL, γ-GT, LDH, ALP and TBA concentrations were measured. HE staining was applied for observation of maternal liver cells degeneration, necrosis and intrahepatic cholestasis. Placental Abcb1a/Abcb1b/HIF-1α mRNA and P-gp/HIF-1α protein expression were determined by real-time quantitative PCR and western-blot. Maternal plasma and fetal-unit digoxin concentrations were detected by a commercial kit assay.

RESULTS

The ICP group showed higher levels of maternal plasma ALT, AST, TB, DBIL, γ-GT, LDH, ALP and TBA concentrations, reduction in fetal survival rates, lower placental and fetal weights, and typical liver cells degeneration, necrosis and intrahepatic cholestasis. The placental Abcb1a mRNA and P-gp expression of ICP group were significantly elevated, while transplacental digoxin transfer rates were significantly decreased. Both placental HIF-1α mRNA and protein expression was significantly elevated in the ICP group, and there was a positive correlation between Abcb1a mRNA and HIF-1α mRNA.

CONCLUSIONS

17α-ethynylestradiol induced ICP could up-regulate placental P-gp expression and reduce transplacental digoxin transfer rate in mice, which might be partly associated with higher expression of HIF-1α.