Local and systemic release of cytokines, nerve growth factor, prostaglandin E2, and substance P in incisional wounds and serum following cesarean delivery

The objectives of this study were to test the feasibility of measuring inflammatory and nociceptive biochemical mediators at the surgical site and to evaluate the relationship between wound and serum levels as well as determine any associations between mediator release, pain, and analgesic consumption after cesarean delivery. Twenty healthy women undergoing elective cesarean delivery with spinal anesthesia were enrolled. Wound exudate and serum mediators, pain scores, and analgesic consumption were measured at 1, 6, 24, and 48 hours after cesarean. In wound exudate, 19 of 20 mediators were reliably detected including interleukin (IL)-1 beta, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, tumor necrosis factor-alpha, interferon-gamma, granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein 1 (MIP-1 beta), nerve growth factor (NGF), prostaglandin E2 (PG-E2), and substance P. Wound PG-E2 and various cytokines peaked early, whereas NGF showed a more delayed release. There were no correlations between the concentration versus time profile of wound and serum cytokines. Analgesic consumption during the first 24 hours after surgery was negatively correlated with IL-1 beta, IL-6, and G-CSF in the wound exudate. This study demonstrates the feasibility of collecting and measuring nociceptive and inflammatory mediators in surgical wounds at specific time points. The lack of significant correlations between wound and serum levels emphasizes the importance of determining site-specific release if localized pathologies are to be studied. Perspective: This study demonstrates the feasibility of measuring real-time nociceptive and inflammatory mediators in surgical wounds. Our findings confirm the lack of correlation between wound and serum levels of many pro-inflammatory and anti-inflammatory cytokines and nerve growth factor. (C) 2008 by the American Pain Society.