Effect of topically supplemented leptin on wound healing in wild-type mice. Balb/c mice were topically treated with leptin as described in Methods. PBS-treated mice were used as a control. (b) Wounded back skin of representative Balb/c mice (5 days after wounding). Wounds have been treated topically for the whole 5-day period after wounding with 5 μg leptin/20 μL PBS twice a day (+leptin) or 20 μL PBS (+PBS), respectively. (a and c) Hematoxylin/eosin-stained frozen sections from 5-day wounds isolated from Balb/c mice that have been treated topically with 5 μg leptin/20 μL PBS twice a day (a) or 20 μL PBS only (c). Arrows indicate the leading edge of the migrating epithelium. e, epithelium; g, granulation tissue; gH, atrophied granulation tissue; he, hyperproliferative epithelium; s, scab.