Objective:To reconstruct pcDNA3.1/VEGF165 and combine it with deproteinized bone(DPB) to repair avascular necrosis of the femoral head (AVNFH).Methods:Clone plasmid pUC18/VEGF165 containing the whole cDNA sequence of VEGF165 was combined with pcDNA3.1(+) to reconstruct pcDNA3.1/VEGF165.Sixty-nine AVNFH model New Zealand adult rabbits with a mean weight of 2.8 kg were randomly divided into three groups.In group 1

DPB combined with the reconstructed plasmid pcDNA3.1/VEGF165 was implanted in the drilled channel of the necrotic femoral head.In group 2

only DPB was implanted.In group 3

only channel was drilled without DPB or plasmid implanted.Femoral head specimens were obtained 3 days

1

2

4

and 8 weeks after operation.The expression of vascular endothelial growth factor (VEGF) was examined by RT-PCR

Western blotting techniques.Angiogenesis and repair of the femoral head were observed by histological and histomorphometric analysis.Results:pcDNA3.1/VEGF165 was reconstructed successfully.In group 1

the expression of VEGF was detected in the femoral head implanted by DPB-VEGF compound.VEGF165 mRNA and protein detected went up to apex 1 week postoperatively and lasted more than 3 weeks.The femoral head implanted by DPB-VEGF compound showed a significant difference in vascularization 2 and 4 weeks after operation and a significant difference in bone formation 2

4 and 8 weeks after operation from those in other groups on histomorphometric analysis (P<0.01).Conclusion:Transfection of VEGF165 gene enhances local angiogenesis in early time and DPB-VEGF compound improves bone formation.Deproteinized bone combined with VEGF gene provides a potential method for treatment of osteonecrosis.