电穿孔介导的基因治疗对兔下颌骨牵引区新生骨骨密度与强度的影响

Objective To explore the effect of electroporation mediated gene therapy on bone mineral density and strength of new-formed bone in mandibular distraction gap, so as to enhance the osteogenesis and shorten the distraction term. Methods New-Zeland rabbits were employed. The distraction began after 3 days of latency period at the rate of 0. 8 mm per day for 7 days. After distraction, the rabbits were randomly divided into 5 groups to receive injection in the distraction gap with recombinant plasmid 2 μg(0. 1μg/μl)pIRES-hVEGF165-hBMP2 in group A, with recombinant plasmid pIRES-hBMP2 in group B, with recombinant plasmid pIRES-hVEGF165 in group C, with pIRES in group D, and with normal saline (NS) in group E. After injection, electroporation was performed in all the groups. After 1 week, 2 weeks, 4 weeks and 8 weeks of consolidation, all the animals underwent X-ray and quantitative computed tomography (QCT). The new-formed bone in distraction gap was selected as regions of interest (ROI) to measure the bone mineral density( BMD). Then the rabbits were sacrificed and the new-formed bone samples were harvested to detect 3-point crushing strength. Results BMD of newly formed bone in group A, B and C was markedly higher than that in group D and E (P < 0. 01 ). After 2 weeks of consolidation, BMD in group A was much higher than that in the other groups, but there was no difference between group B and C. After 4 weeks of consolidation, BMD in group A and B was markedly higher than that in group C, D and E ( P < 0. 01 ). After 8 weeks of consolidation, BMD in group A was markedly higher than that in the other groups. While the BMD was not significantly different between group B and C, but the BMD in group B and C was higher than that in group D and E ( P < 0. 01 ). After 4 weeks of consolidation, the 3-point crushing strength of newly formed bone in group A was markedly higher than that in group B,C, D and E ( P < 0. 01 ) , which was still the same after 8 weeks of consolidation. And the crushing strength in group B was higher than that in group C, D and E ( P < 0.05 ). Conclusions Electroporation-mediated transfection of recombinant plasmid pIRES-hVEGF165-hBMP2 could greatly enhance osteogenesis and calcification. A combination of VECF and BMP may promote osteogenesis and angiogenesis simultaneously, so as to magnify the effect of each growth factor, resulting a synergetic effect.

The effect of electroporation mediated gene therapy on bone mineral density and strength of new formed bone in mandibular distraction gap in rabbit