Trauma-hemorrhage delays wound healing potentially by increasing pro-inflammatory cytokines at the wound site

Background. Studies indicate impaired wound healing after trauma. The under lying mechanism remains unknown. Methods. Mice were subjected to midline laparotomy and polyvinyl alcohol sp onges were implanted subcutaneously before hemorrhage (35 +/- 5 mmHg for 90 minutes,, resuscitated) or sham operation. Wound exudate cells from the sp onges were harvested on the first, third, and fifth postoperative day and c ultured for 24 hours. Interleukin (IL)-1 beta, IL-6, monocyte chemotactic p rotein-1 (MCP-1), macrophage inflammatory protein-2 (MIP-2), and transformi ng growth factor (TGF)-beta were determined in the supernatnants. IL-1 beta and IL-G were measured in the wound fluid. Results, Hemorrhage decreased collagen deposition in the wound. TGF-beta re lease was significantly decreased on the first and third postoperative days after hemorrhage: whereas IL-IP and a-G release was increased at 3 and 5 d ays after hemorrhage. Similarly IL-IP and IL-B in the wound fluid were sign ificantly increased at 3 days after hemorrhage. Conclusions. Because increased levels of pro-inflammatory cytokines and dec reased amounts of TGF-beta have been reported to impair the process of woun d healing, the increased release of IL-1 beta and IL-6 and the decreased re lease of TGF-beta after hemorrhage might contribute to the decreased collag en production in those animals. Thus, attempts to locally change the ratio of those cytokines in trauma victims might be useful for im;improving wound healing in those patients.