The Expression And Significance Of BSEP In ICP Placenta

Background BSEP is a bile acid substrate specific transporter with ABCB11genetic coding, which can transfer bile acid from hepatocytes into bile capillaries and playan important role in the process of bile transfer. BSEP restraint induces bile retentionresulting in intrahepatic cholestasis. Mutation of BSEP is related to bile obstructionaccording to the reference。With immunofluorescence stained, BSEP is obversed located oncanaliculi membrane which is obviously reduced in hepatocytes in intrahepatic cholestasisof pregnancy （ICP）. Gene sequencing of BSEP protein finds three mutations whichindicates that BSEP may be much involved in ICP。Previous studies mainly focus on ICPhepatocytes or ABCB11gene mutations. This study discusses BSEP expression in terms ofplacenta in ICP patient providing a new thought of ICP pathogenesis.Method The expression of BSEP is assayed with immunohistochemical staining on30placentas in ICP and30placentas in normal pregnancy. Another8samples are selectedfrom ICP and normal pregnancy respectively and analyzed the expression of BSEP bywestern blot. Use Alpha image processing to scan the X films from Western blot, measurethe grey level and analyze the difference in BSEP expression between ICP and normalpregnancy.Result The immunohistochemical staining results show distribution of BSEPprotein is on syncytiotrophoblast and in kytoplasm. The positive rate of BSEP proteinexpression is76.7%（23/30）in placenta of ICP set and36.7%（11/30） in placenta ofnormal pregnancy. It indicates a significant statistical difference between these two samplesets （P<0.05）. BSEP grey level is （0.754±0.274） in the placenta of normal pregnancybut reduced to（0.193±0.122） in the placenta of ICP, showing a significant statisticaldifference （P<0.001）.Conclusion BSEP protein expression distribution is obvious in placenta of normalpregnancy which may mediate the transfer process of bile acid between baby and mother. In placenta of ICP, BSEP protein reduces significantly which may be a reason of ICPpathogenesis.