Ischemia-reperfusion injury in chronic pressure ulcer formation: A skin model in the rat

Most animal models of chronic pressure ulcers were designed to study only t he role of ischemic injury in wound formation, often using single applicati ons of constant pressure. The purpose of this study was to develop and char acterize a reproducible model of cyclic ischemia-reperfusion injury in the skin of small un-anesthetized animals using clinically relevant pressures a nd durations. Ischemia-reperfusion injury was created in a 9 cm(2) region o f dorsal skin in male rats by periodically compressing skin under a pressur e of 50 mm Hg using an implanted metal plate and an overlying magnet. We va ried the total number of ischemia-reperfusion cycles, examined the effect o f varying the frequency and duration of ischemic insult, and compared ische mia-induced injury to ischemia-reperfusion-induced injury with this model. Tissue injury increased with an increasing number of total ischemia-reperfu sion cycles, duration of ischemia, and frequency of ischemia-reperfusion cy cles. This model generates reproducible ischemia-reperfusion skin injury as characterized by tissue necrosis, wound thickness, leukocyte infiltration, transcutaneous oxygen tension, and wound blood flow, Using this model, the biological markers of ischemia-reperfusion-induced wound development can b e studied and therapeutic interventions can be evaluated in a cost-effectiv e manner.