OBJECTIVETo investigate the effect of topical application of leptin in promoting burn wound healing in rats.

METHODSFour parallel second-degree burn wounds induced on the back of 18 Wistar rats were divided into leptin treatment group (treated with topical application of 400 ng/ml leptin dissolved in PBS) and control group (treated with PBS). The time of wound healing was recorded, and the wound area that was not healed was measured at 3, 7, 11, 15, and 19 days after burns. The tissue at the peripheries of the wound was sampled at 7, 14 and 21 days after burns for pathological examination with HE staining and immunohistochemistry for proliferating cell nuclear antigen (PCNA) to evaluate the proliferation of keratinocytes.

RESULTSCompared with the control group, leptin-treated wounds showed a shorter time (by 2-3 days) of wound healing, and significant differences were found between the two groups in healing at 7, 11, 15, and 19 days after burns. HE staining and immunohistochemistry revealed a faster rate of epidermis growth and a greater thickness of the cuticular layer in leptin-treated wounds at 7, 14 and 21 days after burns. PCNA positivity in the keratinocytes was stronger in leptin-treated wounds than in the control wounds at 7 and 14 days, but no such distinct difference was noted at 21 days between the two groups.

CONCLUSIONTopical application of leptin can promote re-epithelization in burn wounds to shorten the wound healing time of burns.