APOPTOSIS IN HUMAN CHORIONIC VILLI AND DECIDUA IN NORMAL AND ECTOPIC PREGNANCY

To investigate possible effects of implantation on apoptosis, we exami ned the cleavage of DNA in human chorionic villi and decidua in intrau terine and ectopic pregnancy. Very limited but detectable cleavage of DNA was recognized in the chorionic villi and decidua in normal pregna ncy. A ladder pattern, characteristic of the apoptotic breakdown of DN A, was present in the villi in tubal pregnancy. High molecular weight DNA was predominant in the decidua in tubal pregnancy. Quantitative an alysis of low molecular weight fragments of DNA revealed a significant increase in the villous tissue, together with a significant decrease in the decidual tissue, in tubal pregnancy as compared to those in nor mal pregnancy. An analysis in situ revealed that apoptotic cells were predominant in the syncytiotrophoblast in tubal pregnancy. In decidual tissue, labelled cells were occasionally seen in normal pregnancy, an d their numbers decreased in tubal pregnancy. The present study demons trates that apoptosis occurs in the villi, but not in the decidua in t ubal pregnancy, unlike the situation in normal pregnancy. Our results suggest that the implantation site might affect the occurrence of apop totic changes in early pregnancy of humans.