Study On The Relationship Between The Expression Of Placental MDR3 And Intrahepatic Cholestasis Of Pregnacy

Object: To explore the expression of placental MDR3 , as well as maternal and umbilical cord serum total bile acids (TBA) and cholylglycine(CG) levels.To evaluate the regulating effect of placental bile salt transporters on fetal bile acid level in ICP.Methods: Maternal and umbilical cord serum total bile acids (TBA) and cholylglycine(CG) level were measured in 20 pregnant women with ICP(ICP group) and 20 normal pregnant women(control group) by radioimmunoassay and velocimetry. The placental MDR3 gene expression was examined by real time RT-PCR.Results: (1) Maternal serum TBA and CG levels were significantly higher than those in the umbilical cord blood in ICP group(25.77±16.64 vs 8.545 ± 5.48) μ mol/L , (3416.087 ± 1986.04 vs 821.839 ± 673.17) μ mol/L(P<0.05).However ,compared to maternal serum TBA and CG levels with those of the umbilical cord blood in control group (3.4±2.508 vs 4.36±3.26) μmol/L, (342.74 ± 234.88 vs 309.32 ± 145.20) μ mol/L, there were no differences (P>0.05). The TBA and CG levels of umbilical cord and maternal serum in ICP group was compared individually with those in the control group,the former was significantly higher than the latter(P<0.05).(2)The MDR3 mRNA was expressed in the placenta of ICP group and in every trimester of normal pregnancy. The MDR3 mRNA expression level in ICP group was lower than that in the control group(P<0.05).(3) There were no significant correlation between TBA or CG level and MDR3 mRNA express level in ICP group and in the control group(P>0.05).Conclusion The results suggested that fetal TBA level of rises and the expression of MDR3 mRNA on placenta falls in patients with ICP.The dysfunction of placenta transport bile acid resulted in fetal cholestasis. This is possibly the mechanism of fetal distress in ICP.