The EPR study of nitric oxide in placenta during preeclampsia.

The aim of the study was to establish alteration of nitric oxide (NO) metabolism in placenta and its role in pathogenesis of physiological and complicated with preeclampsia (PE) pregnancy. Fifty women with preeclampsia and 30 control pregnant women were studied. The control group was selected from healthy pregnant women; the preeclamptic group consisted of women who were normotensive before pregnancy and during the first 20 weeks of gestation, and developed hypertension associated with new onset proteinuria. NO content in placenta was studied by Electron paramagnetic Resonance (EPR) method. During pregnancy complicated with PE intensity of EPR signal of adrenodoxin FeS-centres reduced (by 60%), of cytochrome Р-450 increased by 60% - compared to the same parametres during physiological pregnancy; intensive EPR signal of spin-trapped Lipoperoxide (LOO.) was also detected; in the EPR spectrum of placenta a significant reduction of free nitric oxide content and intensive signals of of nitric oxide complexes with hemic and nonhemic iron were detected. These complexes indicate on the nitrosilation of mitochondrial electron transport proteins with following alterations of their activity and disorders of energo- and steroidogenesis processes in placenta during PE. Alterations of placental nitrosilated complexes during PE suggests that NO plays an important role in the regulation its functions.