A new model for studying re-epithelialization of partial-thickness wounds in hypoxic skin

Although some degree of hypoxia is a normal result of acute tissue injury a nd may even stimulate normal repair, chronic ischemia is clearly a patholog ical condition that inhibits normal healing. It has been reported that peri pheral arterial disease accounts either in whole or in part for 10 percent to 20 percent of all leg ulcers. The purpose of this study was to develop a n ischemic wound model in the pig. The pig in many ways most closely approx imates human cutaneous wound healing. To achieve this purpose, eight flaps, four ischemic and four control, were placed on five female pigs. Partial-t hickness wounds were then created on the flaps. The wounds were serially ev aluated histologically to determine the rate of healing. Additionally, tran scutaneous oxygen levels were monitored to determine the degree of hypoxemi a in the flaps. Significantly delayed reepithelialization of wounds was obs erved in the distal wounds on the ischemic flaps as compared to controls (p <0.05) as shown by mean percentage of reepithelialization. Also, a signific ant oxygen gradient was observed within the flaps, and all flap locations h ad significantly decreased oxygenation as compared to control areas measure d (p<0.05). This model allows for the investigation of the effects of a hyp oxic environment on these processes in vivo. Use of this model may allow fo r the evaluation of the effects of hypoxemia on wound healing, remodeling, and infection. This model may also prove valuable for the investigation of various wound treatments in a hypoxic setting.