Animal Models of Ischemic Wound Healing: Toward an Approximation of Human Chronic Cutaneous Ulcers in Rabbit and Rat

Chronic wounds are defined as wounds that heal with a significant delay, usually over a period of more than 2 mo. The morbidity associated with delayed wound healing imposes an enormous social and financial burden on the health care system. Clinical observations suggest that persistent tissue ischemia in the vicinity of the wound is an important underlying feature of chronic wounds that severely impairs the healing process. Prolonged ischemia subjects wounds to infection, inflammation, and necrosis and is a significant contributor to delayed healing in the settings of diabetes, pressure sores, peripheral vascular disease, and venous stasis. In addition, research shows that the physiological response to wounding is deranged in the elderly. This cumulative effect has been demonstrated when topical agents that improve wound healing in the young failed to work in the aged (1 -3 ).