The apoptotic consequences of p53 and Mdm2 siRNA knockdown in human placental villous explants.

<p>(<b>A</b>) Transfection of placental explants with fluorescent labelled non-silencing siRNA demonstrating the presence of siRNA in cytotrophoblast (CT) and syncytiotrophoblast (ST). (<b>B and C</b>) Quantitative PCR demonstrating significant reductions in p53 and Mdm2 respectively, in explants treated with p53 or Mdm2 siRNA (*p&lt; 0.05, **p&lt;0.01, n = 6). (<b>D and E</b>) Western blot densitometry and immunohistochemistry showing a reduction in Mdm2 protein following treatment with Mdm2 siRNA. p53 expression is increased in trophoblast cytoplasm and nuclei in response to Mdm2 siRNA. (<b>F and G</b>) TUNEL index and images respectively, showing apoptosis significantly increased in explants exposed to Mdm2 siRNA (*p&lt;0.05). Elevated apoptosis confirmed by M30 immunostaining with examples imaged by electron microscopy. (<b>H</b>) Proliferative index and representative images showing significantly reduced proliferation in explants cultured with Mdm2 siRNA (*p&lt;0.05). (<b>I</b>) density of syncytial nuclear aggregates (SNA) increased by treatment Mdm2 siRNA (*p&lt;0.05), representative images of control and Mdm2 siRNA (arrow = SNA). Representative images shown (FC = fetal capillary, IVS = intervillous space, CT = cytotrophoblast, ST = syncytiotrophoblast). All scale bars = 10 µm.