Apoptotic and proliferative activities in first trimester placentae

Apoptosis and cell proliferation are widely recognized to be important phys iological processes which together maintain tissue homeostasis. The apoptot ic and proliferative processes in 38 first trimester placentae were quantif ied using terminal deoxynucleotidyl transferase mediated dUTP nick end-labe lling (TUNEL) and an antibody against Ki-67 antigen, respectively. In 14 ca ses, the estimation of apoptotic index was repeated with sections stained w ith haematoxylin and eosin by identifying the morphological features of apo ptosis. We found that the indices obtained by either method correlated well with each other although a lower rate was obtained with the haematoxylin a nd eosin stained sections. Apoptosis was found in clusters mainly in syncyt iotrophoblasts in association with fibrinoid deposits while proliferating a ctivity was limited to cytotrophoblasts and stromal cells. A significant in verse correlation was observed between the proliferative index and gestatio nal age as well as the apoptotic index. While the extent of apoptosis decre ased with advanced gestational age, the correlation was not statistically s ignificant. These findings provide a potential explanation for villous remo delling during trophoblastic invasion in early pregnancy. (C) 1999 W. B. Sa unders Company Ltd.