The Effect Of Transvaginal Ultrasonography On The Apoptosis Of Chorionic Villi In The First-Trimester Pregnancy

Objective In assisted reproductive technologies, transvaginal ultrasonography(TVU) is increasingly used to observe follicle growth or multifetal pregnancyreduction in the early stages of genesis, but the safety of TVU to embryo and fetus are notsure. The aim of the present study was to investigate the effect of TVU on the apoptosisof chorionic villi cells in first-trimester pregnancy.Methods 60 healthy women in first-trimester pregnancy were randomly divided into 4 groups according to different exposure time: control group (bland radiation) , 3min, 5min and 10min. Gestation sacs were radiated by TVU with 5.0-MHz transducer. The chorionic villi were collected 24 hours after exposure. The apoptosis of chorionic villi cells were analyzed by TUNEL. The expression of Bax and Bcl-2 proteins were analyzed by immunohistochemistry.Results The apoptosis cells of chorionic villi were increased according to the time of exposure. In contrast with the control group and 3 min groups, the apoptosis cells were increased significantly in 5 min and 10 min groups (P <0.01). There was no difference between control group and 3 min group (P>0.05) . The expression the Bax in syncytiotrophoblast and cytotrophoblasts were increased significantly in 10 min group (P <0.01) . The expression of Bcl-2 decreased in 3min, 5min and 10min groups in contrast with control group, but there were no difference between the four groups (P >0.05) .Conclusions1. There are small amounts of apoptosis cells in the chorionic villi. The apoptosis cells exit mostly in the syncytiotrophoblasts, but rarely in the stromal cells. And there are no apoptosis cells in the cytotrophoblasts.2. The apoptosis of chorionic villi cells increased after the exposure to TVU, and the apoptosis index increased according to the time of exposure. The apoptosis index was highest in the 10min group, but there was no difference between control group and 3 min group.3. There are small amounts of Bax protein in the cytoplasma of syncytiotrophoblasts, but it expressed rarely in the cytotrophoblasts and stromal cells. Bcl-2 ptotein mostly exited in the cytoplasm of cytotrophoblasts, but it did not expressed in the syncytiotrophoblasts.4. The expression of Bax protein in the cytotrophoblasts and syncytiotrophoblasts increased after the exposure to TVU, and it was accoding to the exposure time. The expression of Bcl-2 protein in the cytotrophoblasts decreased after the exposure to TVU, which was independent on the exposure time.5. In the early pregnancy stage, it is safe to expose the fetus to TUV within 3 minutes. And it is almost safe within 5 minutes. But the time expose to TUV should not longer than 10 minutes.