Effect of tocolytics on interleukin-8 production by human amniotic and decidual cells

Preterm labor is associated with the release of various cytokines that play an important role in its pathophysiology. In preterm labor, tocolytics are used to inhibit uterine contractions and prolong gestation. We tested the hypothesis that tocolytics alter endotoxin-induced interleukin (IL-8) production from amniotic and decidual cells in vitro. Amniotic and decidual cells were isolated from patients undergoing elective repeat cesarean section at term. Cells were grown in tissue culture flasks. Cells were subsequently incubated with 100 ng/ml of endotoxin in 24 well plates in the presence of increasing concentrations of magnesium sulfate, nifedipine and terbutaline. After 24 h, IL-8 levels in each well were measured by ELISA. Endotoxin caused a significant elevation in IL-8 production in both amniotic and decidual cells. Magnesium sulfate dose dependently inhibited the endotoxin-stimulated IL-8 production in both decidual and amniotic cells. However, nifedipine and terbutaline did not significantly affect IL-8 production in either cell type. In conclusion, magnesium sulfate differentially suppresses endotoxin-stimulated IL-8 production in amniotic and decidual cells in vitro. The cellular mechanisms of this suppression and its clinical relevance in the setting of preterm labor merit further investigation.