Effects of magnesium sulphate on placental expression of endothelin 1 and its receptors in preeclampsia

Objectives: To investigate the effects of magnesium sulphate (MgSO4) on placental expression of endothelin 1 (ET-1) and its receptors in preeclampsia (PE). Design and methods: Placentas were obtained from 10 normotensive (NT group) and 18 moderate preeclamptic (PE group) women. Among the PE group, 10 patients were treated with 0.9% NaCl solution (PES) and 8 women received MgSO4 (PEMgSO4). Placental mRNAs of ET-1, ET-1A receptor (ET-1AR) and ET-1B receptor (ET-1BR) were evaluated by Northern blot and quantified using densitometry. Results: Placental ET-1BR expression was lower (P < 0.05) in the PES group without significant changes in the mRNAs of ET-1 and ET-1AR when compared with the NT group. MgSO4 treatment was associated with decreased ET-1 and increased ET-1BR (P < 0.05) expression, without significant changes in ET-1AR. Conclusions: The results of the present study showed that moderate PE is associated with low placental expression of ET-1BR, and MgSO4 treatment resulted in placental expression changes of the ET-1/receptors system.