The immunolocalization of Bcl-2 in human term placenta.

PURPOSE: To study the immunolocalization of the Bcl-2 protein in formalin-fixed placental tissue collected from uncomplicated term pregnancies. METHODS: A total of 19 human term placentas of 38-41 weeks' gestation, 11 obtained from spontaneous deliveries and eight from elective caesarean sections prior to labour were included. Sections were incubated with an antibody to the Bcl-2 protein and light microscopy was used to evaluate Bcl-2 staining. RESULTS: The anti-apoptotic Bcl-2 protein was expressed diffusely throughout the cytoplasm of the syncytiotrophoblast with much less intensive staining in cytotrophoblast and mesenchymal cells. Bcl-2 expression was reduced or lost in areas of syncytial sprouts. No differences in Bcl-2 staining were observed between placentas obtained after spontaneous deliveries and those collected before the onset of labour after elective caesarean section. CONCLUSION: Expression of the anti-apoptotic Bcl-2 protein in human term placenta does not seem to be influenced by parturition. Additionally, Bcl-2 expression might be an important factor in the regulation of apoptosis in the human trophoblast and thus in maintaining placental function during gestation.

Immunohistochemical detection of apoptosis in the human term and post-term placenta.

PURPOSE: To study the incidence of apoptosis in human term and post-term placenta and to determine its presence in different areas of placentas of uncomplicated pregnancies. METHODS: A total of 15 placentas, 8 obtained from spontaneous deliveries and elective caesarean sections at term (37-41 weeks of pregnancy) and 7 from spontaneous deliveries and elective caesarean sections post-term (> 41 weeks of pregnancy) were included in this study. Apoptosis was identified by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling method (TUNEL, Boehringer, Mannheim, Germany) in paraffin-embedded sections. RESULTS: Apoptosis was predominantly detected in trophoblast and stromal tissue. There were no significant differences in the incidence of apoptosis in different parts of placental tissue. A significant increase of apoptosis was seen in both trophoblast and stromal cells of post-term placentas (p < 0.05; p < 0.005). CONCLUSIONS: Apoptosis could be detected in the human term and post-term placenta, with increasing incidence in post-term placental tissue, suggesting a possible role of apoptosis in the mechanism of parturition and placental senescence.