The Histochemical Localization and Activities of Nitric Oxide Synthase in Placental Tissue from Pregnancies with Abnormal Umbilical Artery Flow Velocity Waveforms / 中华围产医学杂志

ABSTRACT

Objective To study the nitric oxide synthase(NOS)distribution and activity in placental villous,stem villous vessel and umbilical vessel from pregnancies with abnormal umbilical artery flow velocity waveforms and discuss the effect of NOS in the development of abnormal umbili- cal artery flow velocity waveforms.Methods Using NADPH-diaphorase histochemical method and colorimetry,we studied the distribution and activity of NOS in placental villous,stem villous vessel and umbilical vessel tissues from nine women with normal umbilical artery Doppler waveforms and eight women with abnormal umbilical artery Doppler waveforms.Results The NOS primarily dis- tributed in the syncytiotrophoblast and vessel endothelial cells.In the majority syncytiotrophoblast of normal group,the blue granules gathered to mass,appeared primarily basal in location.In the ma- jority syneytiotrophoblast of abnormal group,the blue granules diffused primarily around nucleus, the staining intension was weaker than normal.Placental villous from the abnormal group had signif- icantly lower activities of NOS than the normal group.Conclusions The lower activities and an abnormal distribution of NOS were found in the placental villous of women with abnormal umbilical artery flow velocity waveforms.The abnormity of NOS may contribute to the development abnormal umbilical artery flow velocity waveforms.