Targeted-ultrasound-mediated Vascular Endothelial Growth Factor Gene Transfection Against Vascular Restenosis: Experimental Study

Objectives: To investigate whether ultrasound-targeted microbubble destruction could improve vascular endothelial growth factor (VEGF) gene delivery and to evaluate the feasibility of this gene delivery technology for the therapy against vascular restenosis after arterial injury.Methods: The plasmid pCDNA3.1(-)/hVEGF165 was constructed. The rabbit models of injured femoral artery were established. Thirty rabbits with injured femoral artery were divided into 5 groups. VEGF gene transfection was performed using VEGF plasmid alone, ultrasound microbubble attached to VEGF plasmid, VEGF plasmid under ultrasound targeted microbubble destruction as well as two control methods (control plasmid alone and control plasmid by means of ultrasound targeted microbubble destruction). After four weeks, the intimal-to-medial area ratio was calculated for harvested injured artery segment by HE stain. Immunohistochemistry were performed to evaluate the proliferation of vascular smooth muscle cell. Simultaneously, RT-PCR and western blot analysis were performed to evaluate the expression level of VEGF.Results: The intimal-to-medial area ratio was significantly decreased in group V+U+M compared with the other four groups (P<0.05). The VEGF mRNA expression and the amount of VEGF protein which were described as the ratio toβ-actin had a significant increase in group V+U+M compared with the other four groups (P<0.05). The VEGF expression in group V+M was enhanced compared with group C, C+U+M and V (P<0.05). No evidence of VEGF mRNA and protein expression difference was observed between group C and group C+U+M. No difference of such expression was observed between group C and group V(P>0.05).Conclusions: The results of our study demonstrate that after the balloon catheter injury in rabbit femoral artery, the plasmid alone can not promote transfer of vascular endothelial. Microbubble can facilitate VEGF gene transfer of vascular endothelial. However, gene transfer by microbubble can not prevent the smooth muscle cell proliferation and neointimal formation. The VEGF gene transfer mediated by ultrasound targeted microbubble destruction not only enhances the VEGF expression but also suppresses neointimal formation. In conclusion, ultrasound targeted microbubble destruction is an efficient technique for gene delivery and has a promising application in the therapy against vascular restenosis.