Particle-mediated gene transfer with transforming growth factor-beta 1 cDNAs enhances wound repair in rat skin

Based on preliminary but variable results with direct DNA transfer into wounds, we evaluated in vivo gene transfer by particle-mediated DNA delivery to rat skin to determine whether overexpression of TGF-beta 1 at the site of skin incisions would result in a significant improvement in repair. Optimization of the method with viral promoter-luciferase reporter constructs indicated that expression of luciferase activity persisted up to 5 d and was promoter, pressure, and site dependent (ventral >dorsal). Using cytomegalovirus (CMV)-driven human alpha-antitrypsin, transgene expression was immunolocalized within keratinocytes of the stratum granulosum at 24 h. We measured tensile strength of skin incisions at 11-21 d in both normal and diabetic rats transfected with TGF-beta 1 expression vectors at surgery. Native murine TGF-beta 1 under an SV40 promoter produced positive effects, while wound strengthening was more pronounced in diabetic animals using a CMV-driven construct, Transfection of rat skin with constitutively active, mutant porcine TGF-beta 1 under the control of the CMV and Moloney murine leukemia virus promoters significantly increased tensile strength up to 80% for 14-21 d after surgery. Transfection 24 h before surgery was more effective. Particle-mediated gene delivery can be used to deliver viral promoter-cytokine expression constructs into rat skin in a safe, efficient, and reproducible fashion, The extent of wound repair, as evidenced by enhanced tensile strength, can be markedly improved in tissues transfected with TGF-beta 1 expression constructs.