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 int o 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 improveme nt in repair. Optimization of the method with viral promoter-luciferas e reporter constructs indicated that expression of luciferase activity persisted up to 5 d and was promoter, pressure, and site dependent (v entral >dorsal). Using cytomegalovirus (CMV)-driven human alpha-antitr ypsin, transgene expression was immunolocalized within keratinocytes o f the stratum granulosum at 24 h. We measured tensile strength of skin incisions at 11-21 d in both normal and diabetic rats transfected wit h TGF-beta 1 expression vectors at surgery. Native murine TGF-beta 1 u nder an SV40 promoter produced positive effects, while wound strengthe ning was more pronounced in diabetic animals using a CMV-driven constr uct, Transfection of rat skin with constitutively active, mutant porci ne TGF-beta 1 under the control of the CMV and Moloney murine leukemia virus promoters significantly increased tensile strength up to 80% fo r 14-21 d after surgery. Transfection 24 h before surgery was more eff ective. Particle-mediated gene delivery can be used to deliver viral p romoter-cytokine expression constructs into rat skin in a safe, effici ent, and reproducible fashion, The extent of wound repair, as evidence d by enhanced tensile strength, can be markedly improved in tissues tr ansfected with TGF-beta 1 expression constructs.