Objective:To construct BimS lentivirus RNA interference(RNAi) vector and to study its infection efficiency by using RNAi technique.Methods:Three interference targets were designed according to the BimS sequence.The single chain primer was annealed into double-stranded oligo sequences,and then connected with vector linearized with Age Ⅰ and EcoR Ⅰ enzyme.The recombinant plasmid was packaged,and the infection efficiency was observed by infecting ACC-2 cells.Results:After amplification,a 337 bp band was appeared in the electrophoresis results of positive clones.Sequence of inserted fragments were identical with the result of DNA sequencing.Restructuring lentivirus was packed in 293T cells,the virus titer was 2 × 108 TU/ml,MOI =20,and the transfection efficiency was 85％.The BmS mRNA relative expression of pFU-GV-BmS-1,pFU-GV-BMS-2 and control group was 0.743 ±0.025,0.466 ±0.023 and 1.266 ±0.042 respectively(between each 2 groups,P ＜0.05).Conclusion:BimS lentivirus virus RNA interference vectors can be constructed,and can efficiently infect ACC-2 cells.

Objective The method of bone lengthening by distraction of callus was used on dog mandible as a model to study the capability and changes of membranous bone during distraction osteogenesis. Methods 15 dogs aged 5～7 months were chosen as the subjects. The operation included a unilateral or bilateral periosteal preserving corti cotomy of mandibular bone, and an introral mini lengthening device were fixed to the buccal side of the mandible. After 7d, the mandible was lengthened lmm/d for 20d and then held in internal fixation for 7～ 140d (1 ～ 20 weeks). Results The dogs were killed at 3 times. Anthropometric measurements, X-ray examination and histological observa tion were conducted and conformed that the distracted bone had formed in the expanded zone successfully. Conclu sion The results suggested that we could use the DO technique in the area of craniofacial clinic. The strong ability of generating new bone in membranous skeleton by DO technique should be further demonstrated in the future.