The effect of topically applied recombinant human growth hormone on wound healing in pigs

The beneficial wound healing effect of the systemic growth hormone (GH) mediated by insulin-like growth factor 1 (IGF-1) has been widely reported. Recent studies have suggested that GH facilitates wound healing not by circulating IGF-1, but by local IGF-1 produced in the wound itself. The aim of this study was to define whether the locally administered GH could accelerate the wound-healing rate. Full-thickness skin defects (diameter 4 cm) were made in the back of micropigs, and GH (2.5 IU/L) was applied every other day for 3 weeks (11 times total). Control wounds were given the vehicle only. The wound sizes were measured weekly by planimetry and biopsies were taken. The wound sizes were significantly reduced in the GH-treated groups as compared with the control group (P < 0.05) each week. Histological and immunohistochemical examination revealed that the production of IGF-1 and collagen 1 in the experimental group increased more than in the control group. The present results suggest that local treatment with GH effectively accelerates wound healing.