Time course of pro-inflammatory (PRO) and anti-inflammatory (ANTI) maternal cytokine response following systemic lipopolysaccharide (LPS) administration

Maternal bacterial infections are associated with an increased risk of preterm labor and may contribute to fetal injury. Maternal cytokines are intrinsic to the inflammatory/immune response. The temporal induction profile of infection may aid in the determination of maternal immune competency, time course of infection, and likeliness of cure. We sought to determine the time course response of pivotal maternal Pro (interleukin-1a [IL-1α], IL-6, and tumor necrosis factor-α [TNF-α]) and Anti (IL-10) cytokines over 24 h following gram-negative bacterial infection. Timed-pregnant (gestation day 18; n = xx) Sprague-Dawley rats received intraperitoneal injection of bacterial LPS (100 μg/kg b.w.). At 1, 6, 12, and 24 h post injection, animals were anesthetized and maternal blood was collected via cardiac punctures. Serum levels of cytokines were determined by ELISA. In response to systemic LPS, maternal serum TNF-α significantly increased and peaked at 1 h, followed by peak elevations of IL-6, IL-1α, and IL-10 at 6 h (Figure). Only the Pro IL-1a remained significantly elevated at 12 and 24 h. Relative levels of Pro and Anti cytokines may predict infection timing with elevated TNF-α indicating acute, while elevated IL-6, IL-1α, and IL-10 (in the absence of TNF-α) indicates latter stages of infection. Maternal IL-10 expression may be essential for the suppression of Pro cytokines following 6 h.