BACKGROUND:: Studies have shown that nano-hydroxyapatite/polyamide 66 (n-HA/PA66) is a kind of high-strength and high-toughness composite material with excellent biocompatibility, biological safety, biological activity and bone conduction ability. OBJECTIVE:: To investigate the effect and feasibility of n-HA /PA66 plate combined with bone marrow mesenchymal cells (BMSCs) transfected with human LIM mineralization protein 1 (LMP-1) gene for treatment of canine femoral fractures. METHODS:: Canine BMSCs were isolated and cultured with density gradient centifugation method and adhesive culture method. The third-generation BMSCs were transfected with Adv-hLMP-1, and then combined with n-HA /PA66 plate. The dog models of femoral fractures were established in 48 dogs and were divided into four groups: Ad-LMP-1 transfection group, non-transfected group, n-HA/PA66 alone group and plate and screw groups. RESULTS AND CONCLUSION:: The failure rate in the transfection group was lower than that in non-transfected group and n-HA/ PA66 plate group at 8 or 12 weeks postoperatively (P < 0.05), and had no statistical difference compared with plate and screw group (P > 0.05). The healing time of the transfection group was shorter than that of the other three groups. The plate in the transfection group was completely fused with canine femoral lateral cortex after 12 weeks of operation, and there was obvious bone formation between material and bone. The plate and canine lateral femoral cortex were only partially fused in the non-transfected group and n-HA/PA66 plate group, and there was no or a small amount of bone tissue formation between material and bone. The treatment of canine femoral fractures with n-HA/PA66 plate combined with BMSCs transfected with LMP-1 gene can get good fixation effects, promote the fracture healing and fusion with autogenous bone, without the need for a second operation to take out, but the strength of materials have some limitations, which must be combined with external fixation in the treatment of canine femoral fractures.Xu XP, Ni WD, Gao SC, Pu C, Huang WH. LIM mineralization protein 1 gene transfected bone marrow mesenchymal stem cells combined with nano-hydroxyapatite/polyamide 66 plate in the treatment of canine femoral fractures. Zhongguo Zuzhi Gongcheng Yanjiu. 2012;16(21): 3838-3842. [http://www.crter.cn http://en.zglckf.com]