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 (MgSO₄) on tumor necrosis factor-alpha (TNF-α) secretion by preeclamptic placentas. Study design. Cotyledons of six, term, normotensive and ten, pre-eclamptic placentas were dually perfused for six hours (6h), with MgSO₄ (6-7 mg %) in the maternal reservoir [normotensive (n = 3); pre-eclamptic (n = 5)], and with control medium (without MgSO₄) [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-α levels using ELISA. Statistical significance was determined using a 2-way analysis of variance. Results. Pre-eclamptic placentas perfused with control medium (without MgSO₄) secreted higher levels of TNF-α 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 MgSO₄ to normotensive placentas did not affect TNF-α levels in the fetal or maternal circulations. However, exposure of pre-eclamptic placentas to MgSO₄ significantly decreased TNF-α 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-α secretion by MgSO₄ 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-α levels in maternal and fetal circulations.