Topical Oxandrolone Reduces Ear Hypertrophic Scar Formation in Rabbits.

BACKGROUND: Wound healing is a complex process. Despite extensive studies, hypertrophic and keloid scars still occur, and can be functionally and cosmetically problematic. In an attempt to prevent hypertrophic scar formation, the effects of topical oxandrolone, using hyaluronic acid as a biomaterial, were studied on ear wounds in rabbits. METHODS: Deep second-degree burns were inflicted on each ear in 10 New Zealand rabbits. On the left ears, considered the control side, hyaluronic acid gel was applied, whereas on the right ears, the study side, a combination of oxandrolone and hyaluronic acid was applied. Dressings were changed every 2 days for 2 weeks. At week 10, biopsy specimens from the postburn scars were harvested for histologic and immunohistochemical examinations. RESULTS: Fourteen wounds were studied, half on the control side and half on the study side. Six hypertrophic scars were encountered on the control side and only one scar was encountered on the study side. In addition, an increased degree of inflammation, an increased amount of collagen and fibroblast cellularity, increased vascularization, and increased myofibroblast activity were observed on the control side. CONCLUSION: Topical administration of oxandrolone using hyaluronic acid as a biomaterial led to better healing and prevented hypertrophic scar formation.

Improved experimental burn model on rabbits.

OBJECTIVE: The goal of our study was to find an easy and suitable skin burn model for rabbits, to identify the temperature and contact time to reach a deep 2nd degree burn, and to find the best wound dressing fixation method. MATERIAL AND METHODS: We used New Zealand male rabbits as experimental models. On a pilot study, with a copper device heated to temperatures between 43-48 Celsius degrees, the burn was inflicted using contact timesof 3, 4, 5, and 7 seconds. The burn depth was evaluated histological. Twenty-four rabbits were used to evaluate four dressing fixation methods: regular dressing with retention bandages; skin stapler; collars and body resin cast. RESULTS: A 2nd degree deep burn was obtained at 43 degrees for 4 seconds. The retention elastic bandages were removed within hours and the skin staplers were removed with teeth leaving wounds on the skin. The collars were more successful but produced superficial neck lesions. The body resin casts were the most successful. CONCLUSIONS: The best contention method was the bpdy resin cast.