Effect of recombinant adeno-associated virus vector-mediated vascular endothelial growth factor gene transfer on wound healing after burn injury

Objective: The purpose of this study was to investigate the effect of recombinant adeno-associated viral (rAAV) vector-mediated human vascular endothelial growth factor (VEGF165) transfer on experimental burn wounds. Design: Randomized experiment. Setting: Research laboratory. Subjects: C57BL/6 male mice weighing 25-30 g. Interventions: Mice were immersed in 80degreesC water for 10 secs to achieve a partial-thickness scald burn. Animals were randomized to receive at two injection sites on the edge of the burn either 1011 copies of the rAAV-VEGF165 or the vector carrying the control and inert gene beta-galactosidase (rAAV-LacZ). On day 14 the animals were killed. Burn areas were used for histologic examination, evaluation of VEGF expression (immunohistochemistry) and VEGF wound content (enzyme-linked immunosorbent assay), determination of wound nitrite, and measurement of messenger RNA (mRNA) for endothelial and inducible nitric oxide synthase (eNOS and iNOS). Measurements and Main Results: rAAV-VEGF165 increased epithelial proliferation, angiogenesis, and maturation of the extracellular matrix. Furthermore, gene transfer enhanced VEGF expression, studied by immunohistochemistry, and the wound content of the mature protein (rAAV-LacZ, 11+/-5 pg/wound; rAAV-VEGF165, 104+/-7 pg/wound). Moreover, VEGF165 gene transfer increased wound content of nitrate. Finally, rAAV-VEGF165 administration enhanced the messenger RNA for eNOS (rAAV-VEGF165, 1.1+/-0.2 relative amount of eNOS mRNA; rAAV-LacZ, 0.66+/-0.3 relative amount of eNOS mRNA) and MOS (rAAV-VEGF165, 0.8+/-0.09 relative amount of MOS mRNA; rAAV-LacZ, 0.45+/-0.05 relative amount of iNOS mRNA). Conclusion: Our study suggests that rAAV-VEGF gene transfer may be an effective therapeutic approach to improve clinical outcomes after thermal injury.