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 and may even stimulate normal repair, chronic ischemia is clearly a pathological condition that inhibits normal healing. It has been reported that peripheral 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 an ischemic wound model in the pig. The pig in many ways most closely approximates human cutaneous wound healing. To achieve this purpose, eight flaps, four ischemic and four control, were placed on five female pigs. Partial-thickness wounds were then created on the flaps. The wounds were serially evaluated histologically to determine the rate of healing. Additionally, transcutaneous oxygen levels were monitored to determine the degree of hypoxemia in the flaps. Significantly delayed re-epithelialization of wounds was observed in the distal wounds on the ischemic flaps as compared to controls (p< 0.05) as shown by mean percentage of re-epithelialization. Also, a significant oxygen gradient was observed within the flaps, and all flap locations had significantly decreased oxygenation as compared to control areas measured (p<0.05). This model allows for the investigation of the effects of a hypoxic environment on these processes in vivo. Use of this model may allow for 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.