A time course study for the development of an immunocompromised wound model, using hydrocortisone

Although wound healing is essentially a physiologic process, some chronic wounds exhibit considerable delay in healing. Often these do not heal perfectly in individuals with low immune profiles. Thus, the present study was undertaken to develop an excision wound model in the immunocompromised state induced by pretreatment with hydrocortisone (HC) 40 mg/kg intramuscularly in male rats. Wounds of 8-mm diameter were made on the preshaved dorsal surface of rats using an Acuderm biopsy punch, following pretreatment with HC. After 14 days HC-treated animals exhibited atrophy of spleen and adrenal glands and a significant reduction of circulating lymphocytes and increase in neutrophils; these changes are indicative of immunosuppressive state of animals. The cell proliferation was significantly affected as shown by decreases in DNA (23%) and protein (11%). Furthermore, there were also significant reductions in tensile strength (37%) and hydroxyproline (33%) contents. These results were further supported by lack of contraction of wound edges. It is concluded that animals primed with HC 1 week prior to wounding developed prolonged immunosuppression, which significantly impaired the wound healing as compared with other groups. Thus, this can be experimentally employed as an immunocompromised wound model for evaluating compounds as novel wound healers suitable for immunocompromised subjects.