Influence of platelet-derived growth factor on microcirculation during normal and impaired wound healing

The aim of the current study was to evaluate the influence of platelet-derived growth factor (PDGF) on skin microcirculation during normal and impaired wound healing. Secondary healing wounds were created on the ears of hairless mice and treated once with 3 microg of PDGF-BB immediately after wound creation. Intravital fluorescence microscopy was used to quantify reepithelialization, revascularization, vessel diameters, vascular permeability, and leukocyte-endothelium interactions up to 24 days after wound creation. Microvascular perfusion was assessed by laser Doppler flowmetry. Wound healing was studied in normal (n = 15) and ischemic skin tissue (n = 15) as well as in mice (n = 17) rendered hyperglycemic by an intravenous injection of streptozotocin 7 days prior to wound creation. Treatment with PDGF accelerated reepithelialization and reduced the time for complete wound closure in ischemic skin from 14.9 +/- 2.5 (control) to 12.3 +/- 1.8 days (p < 0.03), and in hyperglycemic animals from 15.0 +/- 2.4 (control) to 12.0 +/- 3.0 days (p < 0.04). Revascularization of these wounds was also significantly enhanced after PDFG application. No other parameters were influenced by the treatment. Normal wound healing was not affected. This study confirms the positive influence of PDGF on wound healing under pathophysiological conditions. The effects in this model seem to be primarily due to the mitogenic potency of PDGF on keratinocytes and endothelial cells. A significant effect on leukocyte activation during the inflammatory process was not observed.