中文摘要：

目的研究syncytin及其受体ASCT2在胎盘发育、子癎前期胎盘中的表达以及缺氧对两者表达的影响。方法实时PCR检测syncytin及ASCT2 mRNA的表达。比较25例正常妊娠胎盘（分妊娠7～12周、30～36周和37～40周三组）syncytin和ASCT2表达的不同；比较8例子癎前期胎盘与正常妊娠胎盘syncytin及ASCT2表达的不同；比较正常和缺氧条件下forskolin诱导BeWo细胞分化成合体滋养细胞时，syncytin及ASCT2表达的变化。结果①与妊娠7～12周相比，syncytin mRNA的表达在妊娠30～36周显著增加（P〈0．05），妊娠37周后减少，但仍高于妊娠7～12周（P〈0．05），ASCT2 mRNA妊娠30～36周起减少（P〈0．05），以后一直维持较低水平。②将对照组胎盘和子癎前期组胎盘孕周匹配后比较发现，子痴前期组胎盘syncytin mRNA表达减少（P〈0．01），ASCT2mRNA表达无明显变化。③BeWo细胞分化成合体滋养细胞时，伴syncy—tinmRNA表达增加和AScT2mRNA表达降低（P〈0．05），缺氧抑制syncytin mRNA的表达（P〈0．05），对ASCT2 mRNA的表达无明显影响。结论Syncytin及其受体ASCT2在胎盘的表达与孕周有关，并参与合体滋养细胞形成的调控，子癎前期合体滋养细胞异常可能与缺氧导致syncytin表达异常有关。

英文摘要：

Purpose A human endogenous retroviral element, designated as syncytin, has been suggested as a contributor to the fusion processes of cytotrophoblasts to syncytiotrophoblasts. We tried to investigate the alterations of syncytin and its receptor ASCT2 expression in placental development and preeclampsia and hypoxia-treated BeWo cells syncytialization. Methods Real time PCR was used to study the syncytin and ASCT2 mRNA expression during placental development in 25 placentas from women without preeclampsia（ranged from 7 - 12, 30- 36 and 37 - 40 weeks of gestation）. The levels of syncytin and ASCT2 mRNA expressions were tested in preeclamptic placentas（n = 8） compared with gestational age-matched controls（n = 8）, and further studied in forskolin induced BeWo cells syncytialization under normanix or hypoxia. Results When compared with 7 - 12 weeks of gestation, the expression of syncytin mRNA increased significantly in 30 - 36 weeks of gestation, then it was reduced after 37 weeks of gestation. The ASCT2 mRNA expression was decreased significantly since 30 weeks of gestation and was relatively stable since then to 40 Weeks of gestation. The expression of syncytin elevated, and that of ASCT2 reduced in forskolin induced BeWo cells fusion. Furthermore, a significant reduction in syncytin mRNA expression was observed in preeclamptic placenta and BeWo cells syncytialization under hypoxia, but no reduction in ASCT2 mRNA expression. Conclusions Syncytin and ASCT2 are involved in modulating cell fusion processes. Disturbed placental function in preeclampsia may be due to hypoxia-reduced expression of syncytin.