Identification of macrophages at the site of peritoneal injury: evidence supporting a direct role for peritoneal macrophages in healing injured peritoneum

Objective: To determine if peritoneal macrophages are present at the site of a surgical injury to the peritoneum during wound healing. Design: Controlled research study. S etting: Academic research laboratory. Experimental Model: A murine model of peritoneal wound healing. Intervention(s): Intraperitoneal injection of polystyrene beads 1 hour after a surgical peritoneal injury to identify peritoneal macrophages. Main Outcome Measure(s): Presence of peritoneal macrophages at the site of the healing wound as determined by intracellular polystyrene beads on transmission electron microscopy 1, 3, 7, and 14 days after injury. Result(s): Peritoneal macrophages were easily distinguished from other cell types by the phagocytosis of polystyrene beads. One day after injury, peritoneal macrophages were adherent to the wound surface. By 3 days, mesothelial cells began covering the peritoneal macrophages at the wound surface and peritoneal macrophages were identified deep within the wound. Seven days after injury, the mesothelial layer was completely reconstituted, but peritoneal macrophages persisted within the healing would below the surface mesothelium. Conclusion(s): These data indicate that peritoneal macrophages are present at the peritoneal injury site throughout the healing interval and are consistent with these macrophages having a critical role in peritoneal wound healing. (Fertil Steril(R) 2000;73:988-95. (C) 2000 by American Society for Reproductive Medicine).