Study On The Mechanism Of Wound Healing Promotion By Leptin

Objective: Leptin is known to promote cutaneous wound healing. The present study was conducted to examine the mechanisms involved in wound healing promotion by leptin and provide experimental basis for possible clinic application.Methods: Full-thickness skin wounds were made on the back of Wistar rats, and the wound healing action of exogenous leptin was investigated after leptin administration in the inflammatory stage (dayl to day6) and in the proliferative phase (day7 to day12). The contents of total protein, collagen, NO, FGF and the expressions of collagen I, iNOS, TGF-beta1 in wound tissues were examined on the 4, 7, and 10 days post-operatively. The mRNA expressions of collagen I, collagen III, iNOS, EGF and TGF-betal genes were also investigated. Furthermore, the effects of leptin on proliferation ability, collagen, NO synthesis, as well as the expressions of collagen I, collagen III, iNOS, EGF, bFGF, IGF-I, PDGF, TGF-betal, VEGF in rat fibroblasts cultured in vitro were also explored.Results: The results indicated that local leptin administration led to a significantly increased, dose-dependent wound healing. The wound healing time was shorter after leptin treatment in the proliferative phase than in the inflammatory stage.The rats treated with leptin at a dose of 1μg/cm~2 wound/day had high contents of total protein, collagen and NO in wound tissues compared with control rats. The expression of collagen I was significantly increased, and the level of collagen I mRNA was also slightly elevated in wounds after treated with leptin. Moreover, the levels of iNOS, iNOS mRNA and EGF mRNA were also slightly elevated in wound tissues after treated with leptin. However, the levels of FGF, TGF-betal and TGF-betal mRNA in wound tissues after treated with leptin were not significantly different from those treated with vehicle.Fibroblasts were cultured for 72 hours with different doses of leptin. Data indicated that leptin significantly increased optical density in MTT assay and also significantly...