[Effect of vascular endothelial growth factor 165 gene transfection on repair of bone defect: experiment with rabbits].

Objective To investigate the influence of vascular endothelial growth factor(VEGF) 165 gene transfeetion on the repair of bone defect.Methods 38 New Zealand rabbits underwent resection of a segment 1 cm in length in bilateral radii filled with absorbable gelatin sponge.Dilated solution of the plasmid pcDNA3.1/VEGF165 was injected into the bone defect of one side and normal saline was injected into the contralateral bone defect.1,2,4,6,8,and 12 weeks later X ray examination was conducted to observe the repair of bone defect,and then 5 rabbits were killed at each time points to take out the bone defects.HE staining was used to observe the bone repair.The levels of merovessel density(MVD)1 and 2 weeks after the operation were observed.RT-PCR was used to detect the mRNA expression of VEGF in the bone defect.Based on the results of RT-PCR the tissue mRNA expression of VEGF65 was detected by real- time quantitative polymerase chain reaction(RQ-PCR).Results X-ray examination showed that there was no significant difference in the wound healing between the two group 1 week after the operation in all rabbits. Some callus could be seen in the experimental group 2 weeks after.Twelve weeks after the operation the reconstruction of bone cortex was completed.Similar process occurred in the control sides but more lately. The MVD level 7 days after of the experimental group was 47.0±7.5,significantly higher than that of the control group(42.2±6.4,t=2.4519,P=0.0179),and the MVD level 14 days after of the experiment group was 69.1±5.4,significantly higher than that of the control group(56.1±6.1,t=8.0347,P= 0.0000).In the experimental group the mRNA expression amounts of VEGF165 could be found 1 week after,gradually increased and peaked 3 weeks after,then decreased,and became stable 6 weeks after.The mRNA expression amounts of VEGF165 in the control group were lower than those of the experimental group. Conclusion Local application of PcDNA3.1/VEGF_(165)vector promotes the expression of VEGF165,and enhances the quantity of the angiogenesis,extra cellular matrix and healing of bone defect.