022 Extracorporal Shock Wave is More Effective than Gene Therapy with TGF-Beta to Reduce Ischemic Necrosis in a Rat Epigastric Skin Flap Model

Abstract

In this study, we evaluated and compared the effectivity of two modalities, gene therapy with adenovirus-mediated transforming growth factor-β and extracorporal shock waves (ESW) therapy, to treat ischemically challenged epigastric skin flaps in a rat model. Thirty male Sprague-Dawley rats were divided into three groups of ten rats each. An epigastric skin flap model, based solely on the right inferior epigastric vessels, was used as the model in this study. Rats received either subdermal injections of adenovirus encoding TGF-β(Ad-TGF-β) or ESW treatment with 750 impulses at 0.15 mJ/mm2. The third group received no treatment and served as a control group. A flap measuring 8 × 8 cm was outlined on the abdominal skin. The TGF-β injections were given subdermally in the left upper corner of the flap just prior to flap elevation, whereas the ESW treatment was immediately after the flap was sutured back to its bed. Flap viability was evaluated seven days after the initial operation. Digital images of the epigastric flaps were taken and areas of necrotic zones relative to total flap surface area were measured and expressed as percentages by using a software program. Overall, there was a significant increase in mean percent surviving area in the Ad-TGF-β group and the ESW-group compared to the control group (ESW-group: 97.7 ± 1.8% vs. Ad-TGF-β: 90.3 ± 4.0% and control group: 82.6 ± 4.3%; p < 0.05). Furthermore, in the ESW group mean percent surviving areas were significantly larger than in the Ad-TGF-β group (ESW-group: 97.7 ± 1.8% vs. Ad-TGF-β: 90.3 ± 4.0%; p < 0.05). We conclude that treatment with ESW enhances epigastric skin flap survival significantly more than Ad-TGF-β treatment and, thus, represents a modality that is more feasible, cost effective and less invasive compared to gene therapy with growth factors to improve blood supply to ischemic tissue.