Optimized mesh expansion of composite skin grafts in rats treated with direct current

Background: The purpose of this study was to determine the optimum autoepidermal and allodermal expansion ratio of each component of a meshed composite skin graft (MCSG) that would lead to successful healing. Methods: Male Sprague-Dawley rats were used as hosts of the MCSG and donors of autologous tissue. Male ACI rats were used as donors of allodermis, MCSGs with open meshed area (autoepidermal/allodermal) of 9:1/1.5:1, 9:1/3:1, 9:1/6:1, or 6:1/6:1 were applied to full-thickness skin defects and treated with a silver nylon dressing (SN) or SN with direct current (DC). Wound size, hair regrowth, and thickness of dermal layer were evaluated at 3 months. Results: MCSGs of 9:1/1.5:1, 9:1/3:1, and 6:1/6:1 mesh ratios healed completely within 3 months with no difference in wound size between SN dressing groups or DC-treated groups. Application of DC reduced MCSG contraction and stimulated regrowth of hair. Conclusion: Fresh autoepidermis can be expanded 6:1 on a 6:1 allodermis or 9:1 on a 3:1 allodermis and achieve successful wound healing.