Levels Of Prostacyclin And Thrmboxane In Intrahepatic Cholestasis Of Pregnancy And Expression Of COX-2 In Placenta

OBJECTIVE We sought to elucidate the mechanism of prostacyclin(PGI2), thromboxane(TXA2) and cyclooxygenase-2(COX-2) in the pathology and physiology of intrahepatic cholestasis of pregnancy(ICP) and their relationship with fetal prognosis ,by detecting levels of PGI2,TXA2 in mother blood , amniotic fluid and umbilical cord vein blood from both ICP and normal late pregnancy (NLP) and the expression of their rate-limiting synthase (COX-2) in placenta.METHODS Radomly selected 25 cases of ICP and 25 cases of NLP as compared group. Collect their mother blood, amniotic fluid and umbilical cord vein blood from both groups during caesatean to determine their PGI2,TXA2 levels by using radio-immuno-assay. And also collect 10 cases of placenta tissues from both groups respectively, to detect the expression of COX-2 in plcenta by immunohistochemistry. Each pregnant was given regular hepatic function test (tranaminase,bilirubin,total bileacid,and so on),and regular fetal surveillance(NST,the S/D ratio of umbilical cord artery).RESULTS The PGI2,TXA2 levels in mother blood of both groups have no significant differences .But in amniotic fluid and umbilical cord vein blood the PGI2 level is lower (ICP vs NLP, p<0.05). And the TXA2 level is higher (ICP vs NLP, p<0.05). The incidence of meconium passage is higher in ICP than in NLP(28%, 12%,p<0.05).There is some certain relationship between fetal weight,meconium passage and PGI2,TXA2 in umbilical cord vein blood and amniotic fluid .but the level of TBA has no relationship with fetal weight and Apgar score. Through immunohistochemistry ,the expression of COX-2 is positive in ICP placenta,negative in NLP.CONCLUSION There may exist endothelium system injury in ICP plcenta ,the vascular permieable capability is reduced. The higher level of TXA2 and lower PGI2 in amniotic fluid and umbilical cord vein blood may have some relationship with fetal weight ,fetal distress and meconium passage. TBA has no relationship with fetal weight. COX-2, as the rate-limiting enzyme of PGI2,TXA2 may play a role in the pathology and physiology of ICP plcental vascular changes.