Lentiviral transfection with the PDGF-B gene improves diabetic wound healing

Background: The treatment of diabetic wounds remains a difficult challenge. The present study investigates whether platelet-derived growth factor (PDGF) lentiviral gene therapy can improve diabetic wound healing in the diabetic db/db mouse. Methods: PDGF cDNA was cloned and lentiviral vectors were constructed with either the PDGF-B or green fluorescence protein (GFP) gene. A 2x2-cm full-thickness dermal wound was made on each db/db mouse. Animals were divided into three groups, with eight animals in each group as follows: group I, empty wound; group II, lentiviral PDGF and group III, lentiviral GFP. Lentiviral vectors were injected into the wounds and healing was assessed at 21 days. Harvested wounds were assessed for residual epithelial gap, granulation tissue area, PDGF expression, collagen formation (picrosirius red), and angiogenesis (CD31 staining). Results: Lentiviral vectors were constructed and transfected dermal fibroblasts demonstrated in vitro production of PDGF mRNA as measured by reverse-transcriptase polymerase chain reaction. Immunohistochemistry for PDGF confirmed successful in vivo transfection of the PDGF gene. At 21 days, reepithelialization and granulation tissue area were similar in all groups. However, there was a statistically significant increase in angiogenesis and substantially thicker, more coherently aligned collagen fibers in the PDGF group compared with controls. Conclusions: PDGF lentiviral vectors were successfully transfected into the regenerated dermis in diabetic wounds. Although reepithelialization was similar among the groups, there was enhanced angiogenesis and collagen deposition in the lentiviral PDGF group. These results demonstrate that lentiviral PDGF transfection of the diabetic wound enhances PDGF production, improves vascularization and collagen organization, and has potential clinical applications in diabetic wound treatment.