Title: Induction of interleukin-1 receptor antagonist in rhesus monkeys after intraamniotic infection with group B streptococci or interleukin-1 infusion
Abstract: OBJECTIVE: Interleukin-1 receptor antagonist is a natural inhibitor of interleukin-1, a cytokine implicated in the initiation of preterm labor after intraamniotic infection. The effects of intraamniotic infection and interleukin-1 infusion on the appearance of interleukin-1 receptor antagonist in amniotic fluid and fetal and maternal plasma were assessed with a monkey model. STUDY DESIGN: On day 130 of pregnancy four chronically catheterized rhesus macaques received intraamniotic inoculations of group B streptococci, three monkeys received intraamniotic infusions of recombinant human interlukin-1β, and three monkeys received buffered saline solution infusions. At timed intervals samples of amniotic fluid, fetal plasma, and maternal plasma were assayed for interleukin-1β and interleukin-1 receptor antagonist by immunoassays. Uterine activity was continuously monitored by intraamniotic pressure catheters and by electromyographic activity. RESULTS: Interleukin-1 receptor antagonist, but not interleukin-1 p, was present in the amniotic fluids of all monkeys before intervention. Infection induced the appearance of interleukin-1β and an increase in interleukin-1 receptor antagonist in the amniotic fluid. Interleukin-1β infusion resulted in a similar increase in the intraamniotic concentration of interleukin-1 receptor antagonist, Both infection and interleukin-1β infusion were followed by the transient appearance of interleukin-1 receptor antagonist in the plasma of all fetuses. The subsequent decrease in plasma levels was paralleled by increased amniotic fluid levels of interleukin-1 receptor antagonist. Interleukin-1β and interleukin-1 receptor antagonist were not detected in maternal plasma. Both infection and interleukin-1 infusion induced preterm labor in all treated animals. CONCLUSIONS: Interleukin-1 receptor antagonist is a normal component of monkey amniotic fluid. Intraamniotic infection or the appearance of interleukin-1β in the amniotic fluid results in increased production of interleukin-1 receptor antagonist. Under physiologic conditions interleukin-1 receptor antagonist in amniotic fluid may inhibit interleukin-1-induced preterm labor.
Publication Year: 1994
Publication Date: 1994-12-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 56
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