In Vivo Animal Wound-Healing Model

Seven male Sprague Dawley rats weighting 200 to 250 g were purchased from Shanghai Laboratory Animal Center in the Chinese Academy of Sciences and housed under specific pathogen-free conditions in animal facility. This study was performed in strict accordance with the standards established by the guidelines for the Care and Use of Laboratory Animals of Shanghai Jiao Tong University and was approved by the laboratory Animal Ethics Committee of Ruijin Hospital (Permit Number: 190). Rats were anaesthetized with an intraperitoneal injection of sodium pentobarbital (40 mg/kg body weight). The backs of the rats were shaved, and the hairs were thoroughly removed by (Nair; Church & Dwight, Australia). Using a 6-mm punch biopsy instrument (Acuderm Inc., Fort Lauderdale, FL), six full-thickness skin wounds, paralleling to the spine, were symmetrically created on the back of each animal. Wounds were left uncovered following surgery. Rats were anesthetized with sodium pentobarbital on days 3 to 10 after the wounding. Meanwhile, four wounds were applied with 0, 10, 50, and 100% ASC-CM individually and the remaining two were allowed to heal spontaneously as blank controls. At each time point, the wounds were photographed and drawn on the transparent tracing paper. The paper was then scanned and the wound size was analyzed using ImageJ software. The unhealed rate was calculated by comparing the unhealed wound area to the original wound area. Eventually, the unhealed rate of each group was normalized by the blank control in the same animal.