PDGF gene therapy enhances expression of VEGF and bFGF genes and activates the NF-kappaB gene in signal pathways in ischemic flaps.
BACKGROUND
Gene therapy is a novel approach for enhancing the viability of ischemic flaps. Expression of growth factor genes pertinent to angiogenesis and activation of genes of relevant signal pathways are imperative for improving flap viability. The authors investigated the gene expression profiles of growth factors and signal transduction pathways in ischemic flaps after PDGF gene therapy.


METHODS
Twenty Sprague-Dawley rats were divided into two groups. The experimental group (n = 10) received the plasmid vector containing the PDGF cDNA injected into the dermis of the flap area, whereas the control group (n = 10) received the physiologic saline. Seven days later, a dorsal random flap was raised. Seven days after surgery, flap viability was assessed, and expression of VEGF, bFGF, TGF-beta1, NF-kappaB, Erk2, Stat1, and Smad2 genes of the NF-kappaB, MAPK, JAK-STAT, and Smad pathways was assessed by quantitative analysis of the products of reverse-transcriptase polymerase chain reaction.


RESULTS
Transfer of exogenous PDGF gene significantly improved flap viability (p = 0.011). Levels of expression of VEGF and bFGF genes in the flap were significantly elevated after PDGF gene transfer (p = 0.0001 and p = 0.001, respectively). Expression of the NF-kappaB gene was significantly elevated (p = 0.041). In contrast, expression of TGF-beta1, and Erk2, Stat1, and Smad2 genes was not changed.


CONCLUSIONS
Transfer of exogenous PDGF gene to ischemic flaps promotes expression of VEGF and bFGF genes and activation of NF-kappaB gene in addition to its effects on the PDGF gene. The finding implies that transfer of the gene of one growth factor ultimately improves the expression of the genes of multiple growth factors. Activation of the NF-kappaB gene suggests that the NF-kappaB pathway may be important in enhancement of flap viability and will likely be a target of future efforts of regulation of signaling process in treatment of ischemic flaps.
Wang
Xiao Tian
XT
Department of Surgery, Roger Williams Medical Center, Providence, RI 02908, USA.
Liu
Paul Y
PY
Tang
Jin Bo
JB
D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D020869:Gene Expression Profiling; D015316:Genetic Therapy; D005822:Genetic Vectors; D006085:Graft Survival / Q000502:physiology*; D016328:NF-kappa B / Q000235:genetics*; D010982:Platelet-Derived Growth Factor / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050794:STAT1 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D051899:Smad2 Protein / Q000378:metabolism; D013524:Surgical Flaps / Q000098:blood supply / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000378:metabolism; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D016328:NF-kappa B; D010982:Platelet-Derived Growth Factor; D050794:STAT1 Transcription Factor; D051899:Smad2 Protein; C497784:Smad2 protein, rat; C494081:Stat1 protein, rat; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2