Advances in Research in Animal Models of Burn-Related Hypertrophic Scarring

Skin burn injuries affect approximately 500,000 people per year in France. After deep burns, functional sequelae associated with hypertrophic and retractile scars are an important public health problem. To understand the pathophysiology of sequelae and evaluate new therapeutic approaches, the use of animal models that should be standard tools is necessary. Some pre-clinical models of hypertrophic scars after burns have been described, but the choice of the appropriate and relevant experimental model is crucial to accurately investigate any therapeutic approach. A variety of hypertrophic scar animal models have been described after burn lesions; none of which being totally satisfactory. The most frequently used is the hypertrophic scar model after skin excision of the ear rabbit, but this model does not reflect burn injuries. The red Duroc pig seems to be the more relevant model of human hypertrophic scarring after burns; however, because of costs and the lack of studies evaluating burn injuries in this species, the domestic pig is most commonly used in burn research. Elevated hypertrophic scars are obtained, but they spontaneously resolve within a year. Although mortality in small animals is higher and creates technical difficulties, many models on nude mice are used in research. Indeed, transplantation of human hypertrophic scar tissue or human skin grafts may induce hypertrophic scarring that can last more than a year permitting additional manipulation and experimentation.