A preliminary study on the evaluation of a novel gene delivery vector-TACS in vitro and in vivo via co-expressing hVEGF and hBMP genes to repair critical-size rabbit bone defects

Abstract

Strategies using gene therapy by nonviral vector to improve bone regeneration have been under research in the past. However, transfection efficiency into local cells, such as marrow stromal cells (MSCs) by each vector is not always high. Now, we fabricate a novel gene vector-thiolated N-Alkylated chitosan (TACS) by modifying of chitosan to overcome this problem. TACS is synthesized by conjugation of thiol group and alkyl group to the chitosan. Transfection efficiency of pcDNA3.1-EGFP into HEK293 with TACS increased significantly when compared with chitosan vector by the fluorescence microscope observation. As a next step, we constructed pIRES-hVEGF121cDNA/hBMP-4 by using molecular cloning as a transfer gene to express angiogenic and osteogenic factor synergistically. Furthermore, using in vivo gene therapy, we evaluated the potential of TACS-pIRES-hVEGF121CDNA/hBMP-4 as a novel strategy for the repair of critical-size rabbit bone defects in vivo. Strategy of TACS-pIRES-hVEGF121cDNA/hBMP-4 gene therapy using TACS as a vector enhanced new bone formation significantly. These results suggest that TACS is a novel and potential gene vector and TACS-pIRES-hVEGF121cDNA/hBMP-4 gene therapy is a feasible and simple effect tool for bone regeneration. Key words: Gene therapy, nonviral vector, chitosan, vascular endothelial growth factor, BMP-4, bone tissue regeneration, tissue engineering.