Effect of electroporation mediated transfecting recombinant plasmid pIRES-hVEGF165-EGFP on angiogene-sis of distraction area during early mandibular distraction osteogenesis

Abstract

Objective To explore the effect of electroporation mediated gene therapy on angiogene-sis of the distraction area during early mandibular distraction osteogenesis (DO). Methods Thirty-two New-Zeland rabbits were randomly divided into 4 groups: group A: recombinant plasmid pIRES-VEGF165-EGFP and electroporation; group B: recombinant plasmid pIRES-VEGF165-EGFP; group C: normal saline (NS) and electroporation and group D: control group. The rabbits were sacrificed at 1d, 3d, 7d and 14d after injection, respectively. The distraction area tissue was removed for histological examination and electron microscopy, and immunohistochemical stain for CD34 was performed to detect the microvessel density. Results Generation of vascular endothelial cells (VEC) in the group A and group B were active, and majority of VEC in groups C and D took on early change of cataplasia and apoptosis. The immunohistochemical stain for CD34 showed that it expressed weakly at the first day after transfection, and at 3,7,14 days after transfection, CD34 of VECs in the distraction area expressed positively. CD34 expression was the strongest in group A (P<0. 05), and there was significant difference among three groups and different time, respectively.Compared to each other, CD34 of VECs expressed positively with a tendency to rise in the groups A and B. But it fluctuated at the level of the expression at the first day in the groups C and D. Conclusion Electroporation-mediated transfecting recombinant plasmid could promote angiogenesis during early stage of mandibular DO. It could promote local vascular proliferation and penetration, increase the blood flow of broken ends in fractured bone. It indicates that electroporation-mediated transfecting recombinant plasmid play an important role in regulating and promoting growth and reparative process of the bone. Key words: Mandible; Distraction osteogenesis; Gene therapy; Electroporation; Vascular endotheilal growth factor