There are many options for preclinical wound healing research. All studies are designed to predict how a particular treatment will behave in a human wound. In vitro studies, particularly those that are performed on human skin equivalent systems can provide relevant data - but what it lacks - is the ability to monitor any pain as a result of the wound and healing. Rodent studies provide an inexpensive method for gaining data, however rodents differ from humans in a number of anatomical and physiological ways. A rodent's hair is dense, the epidermis and dermis is thin, and healing is primarily through contraction.