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BACKGROUND: Bone morphogenetic protein 2 (BMP-2) and vascular endothelial growth factor 165 (VEGF-165) play important roles in bone repair. It is of great significance to treat bone injury by lentivirus-transfected bone marrow mesenchymal stem cells combined with demineralized bone matrix. OBJECTIVE: To observe the therapeutic effects of bone marrow mesenchymal stem cells with lentivirus-mediated BMP-2 and VEGF-165 co-transfection and demineralized bone matrix in a rabbit model of osteonecrosis of the femoral head, so as to explore the feasibility of dual genes in the bone repair. METHODS: Femoral head necrosis model was prepared by liquid nitrogen freezing combined with core decompression. Rabbit models successfully prepared were divided into three groups (n=12/group): non-transfection group, treated with bone marrow mesenchymal stem cells combined with demineralized bone matrix; single gene transfection group, treated with BMP-2-transfected bone marrow mesenchymal stem cells combined with demineralized bone matrix; dual-gene transfection group, treated with BMP-2 and VEGF-165 co-transfected bone marrow mesenchymal stem cells combined with demineralized bone matrix. Four rabbits from each group were sacrificed at 3, 6, and 9 weeks postoperatively. Western blot was used to detect the expression of BMP-2 protein in the femoral head of each group. Hematoxylin-eosin staining was used to observe the repair of femoral head necrosis in each group. The study protocol was approved by the Animal Ethics Committee of Guilin Medical University. RESULTS AND CONCLUSION: BMP-2 positively expressed in all groups at 3, 6, and 9 weeks postoperatively, and the positive expression of target protein was significantly higher in the two transfection groups than the non-transfection group (P < 0.05). The positive expression of BMP-2 in the two transfection groups showed an increasing trend at three time periods. At 3 weeks postoperatively, there was no difference in the BMP-2 expression between the two transfection groups, while the BMP-2 expression was significantly increased in the dual-gene transfection group compared with the single gene transfection group at 6 and 9 weeks postoperatively (P > 0.05). In the dual gene transfection group, new osteophytes could fill in the defect of the femoral head at 9 weeks postoperatively, while in the other two groups, new osteophytes formed were not enough to fill in the defect. Hematoxylin-eosin staining indicated that primary trabeculae were formed in the non-transfection group, but there were more necrotic cells and less bone trabeculae. In the single gene transfection group, a large amount of trabeculae formed with good shape, some of which however were inferior to normal bone tissues because of fractures. In the dual gene transfection group, a mass of mature and dense trabeculae were formed and had normal shape. To conclude, lentivirus-mediated BMP-2 and VEGF-165 co-transfection is superior to single BMP-2 transfection in the combination of bone marrow mesenchymal stem cells and demineralized bone matrix for treating femoral head necrosis. Moreover, in vivo expression of target protein persists for a long time. [ABSTRACT FROM AUTHOR]