Abstract
Skin flaps are extensively used in reconstructive surgeries to repair large defects and deep wounds, but severe ischemia and necrosis often results in loss of the transplanted tissue. Thus, skin flap models are often used to study the biology of healing and necrosis of acute ischemic wounds. Delivery of exogenous vascular endothelial growth factor (VEGF) to areas of ischemia has shown promise for promoting therapeutic angiogenesis, but its expression must be tightly regulated to avoid adverse effects. In this study, plasmid DNA encoding VEGF(165) (pVEGF) was delivered to the ischemic skin of a rat skin flap model by intradermal injection followed by electroporation (EP) (pVEGFE+). Treatment with pVEGFE+ significantly increased VEGF expression for 5 days after delivery compared to injection of pVEGF without EP (pVEGFE-). The short-term increase in VEGF was sufficient to mediate an upregulation of endothelial nitric oxide synthase, an angiogenic factor that increases vascular permeability. pVEGFE+ significantly increased skin flap perfusion at both days 10 and 14 postoperatively. The observed increase in perfusion with pVEGFE+ correlated with an increase in skin flap healing and survival. Our results demonstrate that pVEGFE+ is a potential nonviral noninvasive therapy to increase perfusion and healing of skin flaps and ischemic wounds.