Possible therapeutic effect of magnesium sulfate in pre-eclampsia by the down-regulation of placental tumor necrosis factor-alpha secretion.

Objective: To examine the effect of magnesium sulfate (MgSO(4)) on tumor necrosis factor-alpha (TNF-alpha) secretion by preeclamptic placentas.
Study Design: Cotyledons of six, term, normotensive and ten, pre-eclamptic placentas were dually perfused for six hours (6h), with MgSO(4) (6-7 mg %) in the maternal reservoir [normotensive (n = 3); pre-eclamptic (n = 5)], and with control medium (without MgSO(4)) [normotensive (n = 3); pre-eclamptic (n = 5)]. Perfusate samples from the maternal and the fetal circulations were collected every 30 min throughout the 6h of perfusion, and examined for TNF- alpha levels using ELISA. Statistical significance was determined using a 2-way analysis of variance.
Results: Pre-eclamptic placentas perfused with control medium (without MgSO(4)) secreted higher levels of TNF-alpha into the fetal and the maternal circulations (1.60 +/- 0.59 pg/mL/g of cotyledon and 14.28 +/- 2.69 pg/mL/g of cotyledon, respectively), as compared to the fetal and maternal circulations of normotensive placentas (0.25 +/- 0.09 pg/mL/g of cotyledon and 6.73 +/- 1.11 pg/mL/g of cotyledon, respectively) (p < 0.01). Addition of MgSO(4) to normotensive placentas did not affect TNF-alpha levels in the fetal or maternal circulations. However, exposure of pre-eclamptic placentas to MgSO(4) significantly decreased TNF-alpha levels in both the fetal (0.89 +/- 0.09 pg/mL/g of cotyledon versus 1.6 +/- 0.59 pg/mL/g of cotyledon; p < 0.05) and the maternal circulations (4.74 +/- 2.78 pg/mL/g of cotyledon versus 14.28 +/- 2.69 pg/mL/g of cotyledon; p < 0.01).
Conclusion: Down-regulation of placental TNF-alpha secretion by MgSO(4) in pre-eclampsia might indicate a possible therapeutic effect for this agent in reducing maternal, endothelial dysfunction and in improving neonatal outcome in pre-eclampsia, by reducing TNF-alpha levels in maternal and fetal circulations.