Acute intrauterine infection results in an imbalance between pro- and anti-inflammatory cytokines in the pregnant rabbit

PROBLEM: Intrauterine infection results in an increase in cytokines. This s tudy compared the time courses for the pro- and anti-inflammatory cytokine responses in 33 pregnant rabbits at 70% gestation. Pro-inflammatory markers were activated nuclear factor-kappa B (NF-kappa B) in placenta and tumor n ecrosis factor-alpha (TNF-alpha) in amniotic fluid. These were compared to the anti-inflammatory cytokine, interleukin-l receptor antagonist (IL-1ra), in placenta and uterus. METHOD OF STUDY: Does were endoscopically inoculated with Escherichia coli through their cervices and sacrificed at six intervals between 0 and 30 hr post-inoculation. RESULTS: Activated NF-kappa B, determined by electromobility gel shift assa y, increased significantly 16 hr after bacterial inoculation (P less than o r equal to 0.05). This was directly mirrored by TNF-alpha concentrations, d etermined by bioassay, in the amniotic fluid. However, IL-1ra levels, deter mined by enzyme-linked immunosorbent assay, did not increase in response to infection. CONCLUSIONS: Intrauterine infection results in an imbalance between pro- an d anti-inflammatory cytokines that may potentiate infection-induced preterm delivery.