THE IMPACT OF FEMUR FRACTURE WITH ASSOCIATED SOFT-TISSUE INJURY ON IMMUNE FUNCTION AND INTESTINAL PERMEABILITY

Alterations in intestinal permeability and immune function were invest igated in a murine femur fracture (FFx) model. We postulated that soft tissue injury associated with closed FFx (crush injury) would result in greater immunosuppression that open FFx (surgical division). AKR mi ce were randomized to four groups (Normal, Sham, Open FFx, Closed FFx) and studied at 24 and 96 h post-injury. Immune function was assessed by splenocyte blastogenic response and class-specific immunoglobulin p roduction. Intestinal permeability was assessed by measurement of whol e blood fluorometry after gavage administration of fluorescein-dextran (FITC-dextran). Closed FFx is associated with increased splenocyte bl astogenesis and increased immunoglobulin production at 24 h post-injur y. This immunostimulatory response was associated with altered intesti nal permeability early after injury (FITC-dextran: .185 +/- .070 Close d FFx vs. .069 +/- .011 Normal, p = .06). immunosuppression was eviden t at 96 h post-injury in the closed FFx group, documented by significa nt reductions in splenocyte blastogenesis to all mitogens studied, The Open FFx group did not demonstrate any reduction in splenocyte blasto genesis at 96 h post-injury. These data suggest that the soft tissue i njury associated with Closed FFx is associated with significant immuno suppression and altered gastrointestinal permeability, which may adver sely affect the host by increasing the relative risk of post-trauma in fection.