The objective of this study was to examine placentas after delivery from normal, healthy patients at term gestation. The placentas were from elective cesarean sections (n = 10, prior to the onset of labor) and spontaneous vaginal delivery (n = 10, after labor). We found that deoxyribonucleic acid laddering was present in all placentas and consistent with the pattern found in tissues that undergo apoptosis. Paraffin-embedded sections of placental villi stained by the in situ terminal deoxynucleotidyl transferase mediated biotinylated dUTP nick end labeling method revealed positive apoptotic nuclei in the placental villi. Reverse-transcriptase polymerase chain reaction demonstrated expression of messenger RNA for testosterone-repressed prostate message 2 and B cell lymphoma/leukemia-2 in the placenta. Our data demonstrate that apoptosis occurs in human term placenta.
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